Hard Disk free space lick after system restore windows 8.1

I did a system restore and after that, the laptop was functioning slowly. I realised that the disk usage was spiking. Later I realised also that I was constanlty loosing free space from my hard disk without downloading anything or any action. I run the windows
performer recorder when the spikes occurs.Link in OneDrive https://onedrive.live.com/redir?resid=26DCEC24336471AC%21106  . Furthermore when the laptop is on idle the disk usage goes to 100%. Task manager shows that most of the usage is from svchost.exe(defragsvc).
(I dont think it is a scheduled act from windows to run defragging at the moment). What could be? Any advice?

Hi,
From your recorder information, we could see these 5 process below take high disk space:
WPRUI.exe
System
vprot.exe
avgui.exe
avgcefrend.exe
Since you run the Windows performance toolkit to trace the log, exclude WPRUI.exe and system. It seems you use AVG product.
I suggest you disable or uninstall them temporarily to check if the disk usage decrease.
Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact [email protected]

Similar Messages

  • How much hard disk free space?

    My mini is used almost exclusively as a media "appliance", hooked up to a large flat panel TV. Installed on the mini itself is the operating system and little more. Attached to it are several (currently 4) large (1 TB) firewire hard drives crammed with movies and TV episodes (I have digitized my extensive DVD collection with Handbrake plus I have nearly stopped buying new DVDs in favor of downloading from iTunes).
    My question is how much (what percentage) of these external drives needs to be left empty in order for them to operate with reasonable efficiency. They are virtually "read only" in that once I have uploaded a video file to them, it sits there until and unless I want to watch it (or unless I decide to download it to my MacBook and/or iPad to take with me for watching on trips).
    I recall reading years ago that one should keep 10% or so of a hard disk free. Elsewhere, I read it should be as much as 20%. But it strikes me that that would mainly apply to a start-up drive that is constantly being read and written to, not a drive like mine that mainly just stores files and occasionally reads from them.
    To re-emphasize, I keep much of my start-up drive free except what's required for the OS so the issue isn't that but just the external storage drives. I hate to waste as much as 400GB of space (100GB on each of four 1 TB drives).

    I think your argument has some validity, but since you have a lot of time and effort invested in this project, I personally wouldn't try to cut things too close to the bone.
    With drives of that size, I'm comfortable with the 10% rule; perhaps even 5%.
    However, with the price of drives falling, perhaps gradually transitioning to larger capacity drives would be a good idea.
    My understanding is that most modern drives dynamically re-allocate data from sectors that the drive controller senses are going to fail -- so having an adequate percentage of "wiggle room" makes sense to me.
    "Wiggle room" may also come in handy if you ever need to rescue a drive using a utility like DiskWarrior, which needs space to rebuild directory structures.

  • Critical Hard Disk Free Space Error on Lenovo G500 after upgrading from Win8 to Win8.1

    I encountered an error with my harddrive after upgrading my Lenovo G500 from Windows 8 to Windows 8.1. The error is coming up under the Lenovo Solution Center. The error reads "Some partition in your hard drive has less than 9.5% of its capacities. It suggests to click on Fix Options; System; Storage Devices. Then it displays Internal Hard Drive ST1000LM024 HN-M101MBB.The solution center now displays 8 different partitions labled as follows:
    Drive Name: Space:
    W: WINRE_DRV. 694.99 MB free of 999.99 MB
    E... EFI SYSTEM 260 MB
    U.. UNAMED PARTITION. 0.97 GB (THIS IS THE DRIVE PRODUCING THE ERROR)
    M. MICROSOFT RESERVED PARTITION. 128 MB
    C. MICROSOFT RESERVED PARTITION. 850.43 GB FREE OF 890.72 GB
    W. WINDOWS RECOVERY ENVIRONMENT. 155.46 MB OF 449.99 MB
    D: WINDOWS RECOVERY ENVIRONMENT. 22.74 GB FREE OF 24..99 GB
    P...PBR_DRV. 1.8 GB FREE OF 13.01 GB
    I have tried to run disk clean up and optimize drives which were suggestions from the Lenovo Solution Center but neither has been successful in removing the error. Any assistance you guys can provide will help me out a lot
    Thanks,
    Dan

    I got an error when i tried disk repair ("the underlying task reported failure on exit - 1 HFS volume could not be repaired, 1 volume could not be repaired"). Is that the source of my problem?
    Hi and a warm welcome!
    Absolutely, good deduction.
    If DU can't fix it after a couple more tries then, your best bets are DiskWarrior from Alsoft...
    http://www.alsoft.com/DiskWarrior/
    Data Rescue II...
    http://www.prosofteng.com/products/data_rescue.php
    This last one would require another HD with plenty of space to recover to.
    Unfortunately, Disk Utility can't fix all that much, and the only other Apple Options are erasing the HD, or installing OSX to a second drive, then using Migration Assistant to move stuff over to the new HD.

  • Hard Disk Free Space Remove

    Hello,
    I am new in MAC OS. I bought a MAC yesterday. I wanted to create a partition on initial Hard Disk. For this i used Disk Utility. And created a partition with FREE SPACE.
    Now i hard disk becomes half. i can't remove FREE SPACE partition. Please help me.
    Thanks

    Regarding Monolingual..... 
    There is a warning for *native English speakers*. Make sure you keep BOTH English and English (United States). 

  • Hard Disk free space dissapears and reappears

    Hi There,
    Lately I've been noticing some very strange fluctuations in the reported "free space" on my HD. I let the disk get quite full (~1GB free or so) and then starting backing up and transferring data to my external HD. But when I started deleting these items the free space on the Hard Disk didn't increase. Then, one week later, it spontaneously goes from 2GB free to 13GB free (which I assume is the right ballpark).
    Any thoughts as to what might be going on?

    Your diagnostic priority, in order, is Disk Utility (Repair Permissions and Repair Disk), then Disk Warrior (a much more powerful version of the Repair Disk function in Disk Utility).
    Mac Janitor is not really going to help much here. Many Mac users turn to Mac Janitor in a knee-jerk way, like the old "rebuilding the desktop" on OS 9, but if your problem is loss of gigabytes of disk space, there is simply no way the plain text logs maintained by MacJanitor can expand to gigabytes in size unless they are writing to the logs constantly without a break.
    Part of your free space fluctuation may be explained by the automatic virtual memory swap file management does, as VM swap files come and go. The less RAM you have, especially under 1GB, the more likely you have VM swap files building up. When you have more than 10GB disk space free, the swap file movements aren't too noticeable. When you get down below 5GB free, swap files take up proportionally more of your free space and have a much higher chance of destabilizing the machine.

  • Hard disk free space and 192Khz/24bit time recording limit...

    Hello, when I try to record a long stuff at high sampling rate... 96Khz or 192Khz - 24bit , the max time that I have is 65 minutes whit the metronome set at 20 bpm, the max recording time limit is not active, and the space of the hard disk is of 900 GB... but I have only 65 minute of recording time... is a big problem when I need to record classical stuff or a Live.
    --- for 12 channels at 192Khz/24bit in 1 hour of recording time the hard disk space needed is aprox 3,9 Gb... how is possible that LP 7.2.1 limit my recording time ???---- if I go down to 48 Khz I have the time of 248 Minutes of recording... ----

    Hello, when I try to record a long stuff at high
    sampling rate... 96Khz or 192Khz - 24bit , the max
    time that I have is 65 minutes with the metronome set
    at 20 bpm.
    Try setting the metronome higer, say 30 or 40.
    There may be a quirk in that the lowest metronome settings don't always give you the most time.
    Failing that, try another application. Do you by any chance
    have the OEM version of Cubase LE or Mackie's Tracktion?
    Both of those will get you more time at 96khz/24.
    (Seems that both of those applications come as freebies with a lot of different hardware)
    You can record the tracks in one app then import them into Logic.
    Pancenter

  • Strange Hard Disk Free space

    Asking for information on Macintosh HD, it shows a used space of about 243 GB, instead summing all the folders and files below the Macintosh HD it gives only about 190GB: where are the 50 GB missing? There is something hidden that I can delete?
    Thanks

    Usually hidden files should not be deleted. However, files you yourself have created, log files, and files from applications you don't use can be deleted. If unsure if a file is associated with a particular application, ask. My FAQ here has several tips on cleaning disk space*:
    http://www.macmaps.com/diskfull.html
    - * Links to my pages may give me compensation.

  • After System Restore windows programs not loading, and other issues!

    To preface this I have no interest in keeping vista on here I have a CD with windows7 setup on it that I would like to install either on a new partition or over the exsisting one but no clue how to do this right, and when I tried booting up from the CD it gave me an error, so I can't do the setup that way, however I did get a version of windows xp (hiren's minixp) to boot from a thumbdrive, however I could not get my wireless internet to work on it. however thru ethernet it did, but need wifi!) I need a computer for tomorrow morning for my new job orientation is done thru a website and I need a computer to use at thehotel (im out of town) so its not an option taking it to a repair shop tomorrow (its sunday and all), or sending back to lenovo plus its outta warranty. 
    Help! I am very novice at best with techy stuff so I will try to explain this the best that I can. I've had a lenovo N500 Laptop running Vista Home Edition for a couple years now. It did not come with any recover cd's or anything like that. It was starting to run slow, so I figured I'd do the old trusty Factory Restore and start fresh, always did the trick on other computers I owned with windows. Well I went through the whole process of restoring it, and did the initial system setup and naming. When it loaded my desktop for the first time it was all downhill from there. There is no IE installed, no default programs would open, instead I got this error message (example when opening Windows Mail).
    C:\Program Files\Windows Mail\WinMail.exe
    The specified path does not exsist.
    Check the patch, and then try again.
    It does this for every program. Here's the thing the only C:\ Drive that shows up is assigned to removable disk. Here are the current labels for my default Drives.
    Lenovo(Q
    ServiceV003(S
    SW_Preload(D
    So I think the issues possibly that when it was reformatted it labeled the drive a different letter, so it's trying to pull the files from the C drive as a path,. but it needs to be q or s or d or something. Keep in mind this is my very novice theory.

    for wireless issue:
    have you checked device managemer for unknown/non-installed devices? you may need to install drivers for your adapters.
    try to press f8 when you see lenovo logo, then load "safe mode with networking", check if the adapters work.
    can you tell us what error you got when you tried to install win7? also, some of applications doesn't come with preloaded systems so you need to install them later ( as windows mail, msn messenger )

  • Mozilla apps won't load after System Restore from TM

    Alas, a hard disk failure which Apple kindly replaced even though It happened 25 days out of 3-year AppleCare. Thanks!
    New hard disk installed, proceeded to do System restore from TimeMachine and everything went perfectly (as far as I can tell) EXCEPT Firefox and Thunderbird. All the other apps are loading and seem to be working as I would expect (I guess I won't know for sure until I've worked for a few days) but Firefox will not load - the icon bounces in the dock for a couple of seconds and then disappears. Out of curiosity, I tired to load Thunderbird (which I seldom use) and not even the icon appears.
    I am using OS-X 10.5.7 with Firefox 3.0.11
    I have tried deleting the apps and the associated files in Library?Application Support and doing a re-install from a fresh download - same result. I tired restoring the apps from TimeMachine using a restore date one day before the HardDisk failure. Same result. I have used MacTuneUp to repair permission. Same result.
    Any ideas why this is happening? I am most surprised that a fresh install didn't help. And it's interesting that two Mozilla apps are affected. I can live without Thunderbird but Firefox is important as there are some websites that still refuse to open with Safari.

    [email protected] wrote:
    OK - that was a good suggestion. Firefox and Thunderbird both work when I log is as a guest. Now what should I be looking for on my main account that is blocking the apps from opening? Thanks for the help.
    probably something in their preferences. the most radical thing would be to delete the whole folders /users/usernmae/library/application support/firefox and /users/username/library/thunderbird. or just move those folders to the desktop. then try starting firefox and thunderbird. however, that will wipe all user info in both apps.

  • Operations Manager log flooded with 11903 errors due to "Virtual Hard Disk free disk space" monitor

    Management Pack: Microsoft Windows Hyper-V 2012 R2 Monitoring (7.1.10104.0)
    Monitor: Virtual Hard Disk free disk space
    There appears to be an issue with this monitor. Every hour, each of my Hyper-V servers is reporting dozens of errors similar to the following. It seems like there is a disconnect between the expected return type (integer) and the actual type (decimal) when
    checking the free space on VHDX files.
    Log Name:      Operations Manager
    Source:        Health Service Modules
    Date:          2/5/2014 7:59:47 AM
    Event ID:      11903
    Task Category: None
    Level:         Error
    Keywords:      Classic
    User:          N/A
    Computer:      BEAST.corp.technologytoolbox.com
    Description:
    The Microsoft Operations Manager Expression Filter Module could not convert the received value to the requested type.
    Property Expression: Property[@Name='Microsoft:9AC8FCAB-800D-424F-ABCB-747063E5FCF1\559D22F4-A565-4AD4-9B71-44FC5D815C0C\0\0\L.FreeSpace']
    Property Value: 488033.99609375
    Conversion Type: DataItemElementTypeInteger(5)
    Original Error: 0x80FF005A
    One or more workflows were affected by this. 
    Workflow name: Microsoft.Windows.HyperV.2012.R2.VirtualDrive.FreeSpaceMonitor
    Instance name: Hard Disk
    Instance ID: {0C0E0759-D846-963C-21E6-3C1A1C096D5F}
    Management group: HQ
    Event Xml:
    <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
      <System>
        <Provider Name="Health Service Modules" />
        <EventID Qualifiers="49152">11903</EventID>
        <Level>2</Level>
        <Task>0</Task>
        <Keywords>0x80000000000000</Keywords>
        <TimeCreated SystemTime="2014-02-05T14:59:47.000000000Z" />
        <EventRecordID>32395</EventRecordID>
        <Channel>Operations Manager</Channel>
        <Computer>BEAST.corp.technologytoolbox.com</Computer>
        <Security />
      </System>
      <EventData>
        <Data>HQ</Data>
        <Data>Microsoft.Windows.HyperV.2012.R2.VirtualDrive.FreeSpaceMonitor</Data>
        <Data>Hard Disk</Data>
        <Data>{0C0E0759-D846-963C-21E6-3C1A1C096D5F}</Data>
        <Data>Property[@Name='Microsoft:9AC8FCAB-800D-424F-ABCB-747063E5FCF1\559D22F4-A565-4AD4-9B71-44FC5D815C0C\0\0\L.FreeSpace']</Data>
        <Data>488033.99609375</Data>
        <Data>DataItemElementTypeInteger(5)</Data>
        <Data>0x80FF005A</Data>
      </EventData>
    </Event>

    SCOM agent is running as SYSTEM. (I used to run SCOM agents as a low-privilege domain account but eventually surrendered to "The Dark Side" due to the number of issues encountered with that approach.)
    PS HKU:\.DEFAULT\Control Panel\International> dir
    Hive: HKEY_USERS\.DEFAULT\Control Panel\International
    Name Property
    Geo Nation : 244
    User Profile Languages : {en-US}
    ShowAutoCorrection : 1
    ShowTextPrediction : 1
    ShowCasing : 1
    ShowShiftLock : 1
    User Profile System Backup Languages : {en-US}
    ShowAutoCorrection : 1
    ShowTextPrediction : 1
    ShowCasing : 1
    ShowShiftLock : 1

  • Best software for doing full backups to ext. hard disk to to be used to restore system

    As a new PC owner I wanted to find out what the best software for doing full backups to external hard disk,  to to be used to restore the system if primary primary disk crashes. Im aware that Windows, Acronis and Paragon all have software that doing varying degress of back and resore functions.

    lasvideo,
    My favorites are ShadowProtect to do an "image backup" of boot drive and Beyond Compare for backing up files for all other "data" arrays. ShadowProtect does not seem to have much market share compared with Ghost and Acronis, but I really love it.
    What I like about ShadowProtect:
    - Extremely fast (complete image backup for 61GB of files on my boot SSD RAID 0 array to a RAID data array takes less than 3 minutes)
    - Can do image backups across a LAN; restores from boot CDROM and USB device
    - Allows for backups from one controller and restore of OS on a different controller and/or RAID configuration (has HAL tools; Hardware ? Layer I think)
    - Can "mount" an image backup as a drive letter and see (and copy) all directories, files, etc. that are contained in the archive
    What I like about Beyond Compare:
    - Can choose what to backup and what to ignore very easily (for example you can set it to ignore certain files or directory names to ignore and then save how you set things up as a "session")
    - Only needs to copy over files that are new or have changed since your last backup
    - Makes it very easy to selectively delete files from your backup
    Regards,
    Jim

  • Need to separate drive alerts with Logical Disk Free Space monitoring in SCOM 2012

    I have an interesting need here to separate our SCOM alerts for Logical Disk Free space so that one alert is for OSSystem drives ONLY (C:/D:) and the other monitor alerts on all APP drives only (E:, etc). So far we have had great success using Kevin Holman's
    blog post.
    http://blogs.technet.com/b/kevinholman/archive/2009/11/24/writing-monitors-to-target-logical-or-physical-disks.aspx
    We have overrides set so that the monitors report ONLY the percentage of free space left and ignores any MB threshold. So far so good, the alert comes in that host A reports low disk space on D: at 2.345...% free or host B reports low disk space on F: at
    4.567...% free space etc. Now that we have our monitors working within the Windows Server classes Logical Disk, we need to set these monitors so that one is just for C or D drives with the alert named system Logical Disk Free Space OS Disk Warn and the other
    monitor just reports on E - Z drives (excluding C or D) with the alert named Logical Disk Free Space APP Disk Warn.
    We are very new to SCOM so I made the rookie mistake of creating a dynamic group for all Windows Server 2003 Logical Disk class that only includes Device Name = C or D. But found out too late you cant point a monitor to a group, it has to target a class.
    And using the current monitors we set up with the above blog uses the correct logical disk class, but it doesnt care what instance (device Id = value), it will report low disk space on ANY logical drive. How in the world can we separate and exclude these monitors
    so that one alerts only on OS disks (C and D) and the other only alerts on app disks (E through Z)?

    Hi Kevsharp,
    Quite confusing after reading your question.
    So based on your requirement, What i understand is you need separate alerts for all the drives of the disk is running at low or out of space right ?
    For the above just create a simple performance counter monitor and use the same counters as kevin has used in his blog.
    Now Target: Use Windows server operating system (This will target all the Windows operating system agents in your SCOM. If the specified discovery MP's are installed).
    Set a threshold Below 10% is critical or what ever. You will get the alerts in your console.
    Gautam.75801

  • Logical Disk Free Space Monitor - Slow to detect low free space

    We are using the built in two trigger (MB and %) logical disk free space monitor in SCOM 2012 R2. We have setup overrides for MB warning and critical for both system and non-system drives and for a group containing disks we do not want monitored. The monitor
    actually works fine, triggering an alert when both the MB and % free criteria are met. The problem is that it takes almost an hour for the initial alert to fire. After the initial alert, if I further fill the disk to push it from warning to critical, the alert
    changes within the specifiec interval, which we have left at 15 minutes. The alert also clears using the 15 minute interval.
    Has anyone else seen this behavior with this monitor? A disk monitor that takes an hour to fire is not going to be very useful.

    I wanted to see for myself if there was anything else that I might be missing, so I opened up the Windows 2008 Logical Disk Free Space monitor XML and noticed that there is a NumSamples configuration that is set to 4. So, if the interval is 15 minutes, the
    disk would have to exceed both threshold types for 4 consecutive intervals in order to change state and generate alert. This would be a minimum of 1 hour before an alert is raised with the default 15 minutes interval.
    Unfortunately, NumSamples is not overrideable in the monitor type, which is too bad... The only way to get an alert sooner than one hour is to override interval. For example, if you want an alert within 20 minutes, override interval to 300 seconds (5 minutes).
    Here is the code - see for yourself:
    <UnitMonitor ID="Microsoft.Windows.Server.2008.LogicalDisk.FreeSpace" Accessibility="Public" Enabled="true" Target="Server2008!Microsoft.Windows.Server.2008.LogicalDisk" ParentMonitorID="SystemHealth!System.Health.AvailabilityState" Remotable="true" Priority="Normal" TypeID="Microsoft.Windows.Server.2008.FreeSpace.Monitortype" ConfirmDelivery="true">
    <Category>Custom</Category>
    <AlertSettings AlertMessage="Microsoft.Windows.Server.2008.LogicalDisk.FreeSpace.AlertMessage">
    <AlertOnState>Warning</AlertOnState>
    <AutoResolve>true</AutoResolve>
    <AlertPriority>Normal</AlertPriority>
    <AlertSeverity>MatchMonitorHealth</AlertSeverity>
    <AlertParameters>
    <AlertParameter1>$Target/Property[Type="Windows!Microsoft.Windows.LogicalDevice"]/DeviceID$</AlertParameter1>
    <AlertParameter2>$Target/Host/Property[Type="Windows!Microsoft.Windows.Computer"]/PrincipalName$</AlertParameter2>
    </AlertParameters>
    </AlertSettings>
    <OperationalStates>
    <OperationalState ID="UnderWarningThresholds" MonitorTypeStateID="UnderWarningThresholds" HealthState="Success" />
    <OperationalState ID="OverWarningUnderErrorThresholds" MonitorTypeStateID="OverWarningUnderErrorThresholds" HealthState="Warning" />
    <OperationalState ID="OverErrorThresholds" MonitorTypeStateID="OverErrorThresholds" HealthState="Error" />
    </OperationalStates>
    <Configuration>
    <ComputerName>$Target/Host/Property[Type="Windows!Microsoft.Windows.Computer"]/NetworkName$</ComputerName>
    <DiskLabel>$Target/Property[Type="Windows!Microsoft.Windows.LogicalDevice"]/DeviceID$</DiskLabel>
    <IntervalSeconds>900</IntervalSeconds>
    <SystemDriveWarningMBytesThreshold>500</SystemDriveWarningMBytesThreshold>
    <SystemDriveWarningPercentThreshold>10</SystemDriveWarningPercentThreshold>
    <SystemDriveErrorMBytesThreshold>300</SystemDriveErrorMBytesThreshold>
    <SystemDriveErrorPercentThreshold>5</SystemDriveErrorPercentThreshold>
    <NonSystemDriveWarningMBytesThreshold>2000</NonSystemDriveWarningMBytesThreshold>
    <NonSystemDriveWarningPercentThreshold>10</NonSystemDriveWarningPercentThreshold>
    <NonSystemDriveErrorMBytesThreshold>1000</NonSystemDriveErrorMBytesThreshold>
    <NonSystemDriveErrorPercentThreshold>5</NonSystemDriveErrorPercentThreshold>
    <NumSamples>4</NumSamples>
    </Configuration>
    </UnitMonitor>
    This proves 2 things:
    1. Your testing proved that the monitor is working as designed - you got an alert in about an hour
    2. This is a bad design at best, or a bug if you wish, as NumSamples should not be a hidden configuration - it should be exposed in override parameters in the console.
    This should be fixed by Microsoft.
    Jonathan Almquist | SCOMskills, LLC (http://scomskills.com)

  • Hard drive free space discrepancy

    I have an 11 inch Macbook Air with a 120GB SSD and I am running OS X Lion 10.7.5.
    Every so often I get messages indicating my hard drive is nearly full. Since it is a small hard drive I never thought much of it and just deleted a movie or two I put on it for when I travel. But lately I realized that I keep all my music, photos, and bulk of my movie files on an external drive, so there really isn’t much on my computer.
    When I add up all the files listed under My Mac HD in the finder, I get 62 GB. Add in the operating system and I come up with 75 GB of the SSD used. When I look at the storage summary on “About this Mac”, it says I am using 94 GB. There is about a 19 GB discrepancy. Does anyone know what could cause this and where 19 GB of data can be hiding?
    Hard drive free space discrepancy

    Use a tool like OmniDiskSweeper 1.8 to find what's on the disk, where, and how large.
    Freeing Up Space on The Hard Drive
      1. See Lion's Storage Display.
      2. You can remove data from your Home folder except for the /Home/Library/ folder.
      3. Visit The XLab FAQs and read the FAQ on freeing up space on your hard drive.
      4. Also see Freeing space on your Mac OS X startup disk.
      5. See Where did my Disk Space go?.
      6. See The Storage Display.
    You must Empty the Trash in order to recover the space they occupied on the hard drive.
    You should consider replacing the drive with a larger one. Check out OWC for drives, tutorials, and toolkits.

  • How can I add new content in iDVD to a DVD-RW disc which has ample remaining free space? After preparing the new video for burning and clicking on Burn to iDVD, I get a window saying the disc's already recorded and that I can either Erase or Eject.

    How can I add new content in iDVD to a DVD-RW disc with a video previously successfully recorded on it? (The disc has ample remaining free space.)
    After preparing the new video for burning and clicking in the File menu on Burn to iDVD, I get a window saying the disc's already recorded and that I can either Erase or Eject. My assumption has been that iDVD would automatically find the free space and continue with the new recording from there. I'd be grateful if anyone can shine light on this.

    There are, but not with a DVD written as a movie disk. It must be closed when completed, or it doesn't work.
    Apple's built in Burn utility also automatically closes any data CD, DVD or Blu-ray disk you burn. Doesn't matter how much space is unused, you can't use it. You'd have to use a more advanced disk creation app, such as Toast Titanium. I then have the option of choosing to write the data as a session:
    I can keep doing this until the disk is full. If I've written five sessions to the disk, when I put it in the drive, five CD/DVD icons will appear on the desktop since the OS will treat each session as if they are separate physical disks. At any point you choose Write Disk when writing a group of data, that means you're closing the disk, and again can't add anything after that. So if I had written two sessions, and the third was Write Disk, it's over. I can't put anything else on that disk.

Maybe you are looking for