Can't zap PRAM

I have a late 2006 20" 2.16GHz iMac. I've had an on and off issue for a couple of months or so where when I boot up it will come up with a grey screen and a lock. I do NOT have a root password enabled or anything like that, so I don't know what the lock is. I restart, and the iMac boots up to the log in screen no problem. This has happened maybe three times in the last two - three months. The harddrive checks out fine, and running a hardware check everything also checks out fine. I can't re-create it on purpose.
Today I installed Snow Leopard, all the updates, repaired permissions, all the usual stuff, and I thought I'd go ahead and zap the PRAM while I'm at it (just in case that helped the other issue above), but I can't seem to do it. I'm holding the Command, Option, P and R keys at start-up. It just starts up as usual. I've tried it from a restart, from shutting down and starting up, I've tried changing my timing (early and late) in how I press the keys, I've held the keys and had someone else hit the power. I have an aluminum keyboard, so I tried switching it out for the regular Apple white keyboard that came with the iMac, no luck. I've unplugged everything from the computer except the keyboard (I even tried unplugging the mouse). I've never had any trouble zapping PRAM on any computer, so I'm just kind of flummoxed...
mj

Are you using the original Apple keyboard? Some after market keyboards aren't properly recognized during startup (until their drivers load).

Similar Messages

Changed startup disk and now iMac won't boot, even to CD, can't zap PRAM

So maybe I did something really bad, but I can't imagine that I've fried my logic board, right? I changed the startup disk to an external CD/DVD drive with a linux boot CD inserted. I rebooted the computer and got just a grey screen. I decided that this computer was not capable of booting from the linux CD. Forced the power off by holding down the power button. I turned the computer back on and removed the linux CD. Now my computer will not boot at all. I get a grey screen, then after a long period, the folder with a flashing question mark.
I tried booting to my system restore CD in order to switch the startup disk back to my internal HDD, but it will not boot to CD, even when holding the 'C' button. I disconnected the external drive after trying to boot from CD using the external or internal CD drive. I tried resetting the PRAM, but the computer will not do this. I noticed that perhaps the keyboard is not being powered because I can't turn CAPS LOCK on and get a green light.
What else could I possibly try before taking a trip to the genius store? I look forward to your ideas.

So get this. I replaced the original keyboard on this computer and was just informed that only the original kybd will work for system startup commands. Since I no longer have the original kybd, the only was to switch the boot drive is use the IR remote that came with the computer, by holding the 'menu' button and using FF and RED buttons to make selection.

I can not attach any files to email or Facebook. When I go to "browse" the window comes up and disappears immediately. I updated browser and Adobe Flash. Restarted computer and zapped pram. any ideas? Please help!

I can not attach any files to email or Facebook. When I go to "browse" the window comes up and disappears immediately. I updated browser and Adobe Flash. Restarted computer and zapped pram. any ideas? Please help!

Please read this whole message before doing anything.
This procedure is a test, not a solution. Don’t be disappointed when you find that nothing has changed after you complete it.
Step 1
The purpose of this step is to determine whether the problem is localized to your user account.
Enable guest logins* and log in as Guest. For instructions, launch the System Preferences application, select Help from the menu bar, and enter “Set up a guest account” (without the quotes) in the search box. Don't use the Safari-only Guest login created by Find My Mac.
While logged in as Guest, you won’t have access to any of your personal files or settings. Applications will behave as if you were running them for the first time. Don’t be alarmed by this; it’s normal. If you need any passwords or other personal data in order to complete the test, memorize, print, or write them down before you begin.
Test while logged in as Guest. Same problem(s)?
After testing, log out of the guest account and, in your own account, disable it if you wish. Any files you created in the guest account will be deleted automatically when you log out of it.
*Note: If you’ve activated “Find My Mac” or FileVault in Mac OS X 10.7 or later, then you can’t enable the Guest account. The Guest login created by “Find My Mac” is not the same. Create a new account in which to test, and delete it, including its home folder, after testing.
Step 2
The purpose of this step is to determine whether the problem is caused by third-party system modifications that load automatically at startup or login.
Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards. Boot in safe mode* and log in to the account with the problem. The instructions provided by Apple are as follows:
Be sure your Mac is shut down.
Press the power button.
Immediately after you hear the startup tone, hold the Shift key. The Shift key should be held as soon as possible after the startup tone, but not before the tone.
Release the Shift key when you see the gray Apple icon and the progress indicator (looks like a spinning gear).
Safe mode is much slower to boot and run than normal, and some things won’t work at all, including wireless networking on certain Macs.
The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.
*Note: If FileVault is enabled under Mac OS X 10.7 or later, or if a firmware password is set, you can’t boot in safe mode.
Test while in safe mode. Same problem(s)?
After testing, reboot as usual (i.e., not in safe mode) and verify that you still have the problem. Post the results of steps 1 and 2.

To BALTWO:I really appreciate the fast sent solution about my failure to burn DVDs with Lion, but I am 89 years old and think I know something about computers, but don't have a clue about ZAPPing PRAM nor RESET SMC. I also can't find any evidence of a p

I really appreciate the fast sent solution about my failure to burn DVDs with Lion, but I am 89 years old and think I know something about computers, but don't have a clue about ZAPPing PRAM nor RESET SMC. I also can't find any evidence of a preserved earlier OS (Snow Leopard). I also don't know how to partition further my drive after all this time…(I used to have Parallels partitioned) but as I said I cannot find any where on the HD SN. Is it possible that it doesn't exist anymore? Not too technical, please, unless that is the only possible answer to this whole delemna..

Blue colored text in these forums usually indicates a clickable link. The two I posted in https://discussions.apple.com/message/18789716#18789716 bring up Apple's articles on those subjects. For partitioning information, peruse Disk Utilities help files, especially
Changing a disk’s formatting and partitions
BTW, the proper way to respond to a post is to use the Reply button and not start another. Good luck and hope you make it to your tenth decade—I'm in my eighth.

Drives stopped mounting with FW800, but FW400 is OK. Worked OK before, but won't now. Tried new cables, zapping pram, Disk Repair Utility. Any suggestions? Thanks.

Drives stopped mounting with FW800, but FW400 is OK. Worked OK before, but won't now. Tried new cables, zapping pram, Disk Repair Utility. Any suggestions? Thanks.

If your external drive does not have an independent power supply, you may wish to consider a couple of lower-cost options before tossing the drive. Bus-powered drives have no external power source and must get all their power from the computer. They can exceed the computer's USB energy budget.
Cheapest option:
1 Meter USB 2.0 A to 5 Pin Mini B Cable - Auxiliary USB "Y" Power Design for external hard drives.
This gets power from two of the computers USB porst sna can provide enough power to wake up an under-performaing bus-powered drive.
If you don't have enough ports to use this, try the next cheapest option:
Newer Technology 7 Port Hi-Speed USB 2.0 Hub with Power Adapter for Mac & PC
Such a hub has a an independent power supply to make up for wahat the comptuer fails to provide.

Unable to download OS X using Zapping PRAM index.

Unable to download OS X using Zapping PRAM index. Gives OS X Mavericks failed to download use the purchases page to try again - But cant see Mac app store icon as screen has completely gone grey
Since yesterday my Macbook Pro is not working - rather I cant see finder and upon booting, instead of any screen savers and icons displaying it is showing a balnk grey screen.
After reading some discussion and watching to some videos on You Tube, I managed to empty my Mac HD by traferring all the files to an external HD and then suing zapping PRAM keys, I got to a screen from where I am trying to download OS X to re install it.
However after some time it is giving error as 'OS X Mavericks failed to download use the purchases page to try again'.
But to access purchase page, I am unable to view Mac app stores application or icon.
Please help in fixing this issue.

Hi there,
Mine is 2011.
I tried the suggestion you gave, but it didnt work.
However can someone help with clarification - mine is 2011 MBP and I reconk that it came with OS X Lion pre-installed and now with OS X utilities page, when I try to reinstall OSX it tries installing Mavericks and fails at certain stage.
When it fails I get pop-up message as 'OS X Mavericks failed to download use the purchases page to try again'
But I am unable to get App stores and go to purchases, as I dont see that option anywhere using OS X Utilities (which is the only way I am able to access my mac once I start)
So, Kindly help whether I need to get OS X Lion reinsalled first and then upgrade OS X Mavericks?
To do so, should I buy OS X Lion (as I dont think there is any back-up of OS available on my machine)?
Any suggestion will be much appreciated.

I have a mid-2010 27" Quad Core i5 iMac running 10.8.3. Startup disk recognizes the primary hard drive as a startup volume but will not boot from it. Have tried zapping PRAM, ran disk utility. No errors reported Any thoughts?

I have a mid-2010 27" Quad Core i5 iMac running 10.8.3. Startup disk recognizes the primary hard drive as a startup volume but will not boot from it. Have tried zapping PRAM, ran disk utility. No errors reported Any thoughts?

My bad Eric. The startup preference recognizes the primary as a 10.8.3 startup volume but when u select it the system does not boot. I can only boot from my external backup drive

Help! zapping PRAM has lost my drive!

I was working my way through various trouble-shooting routines and read something here which led me to try zapping the PRAM (control-optionP+R on restart) which gave me the expected two chimes but left me with a blinking disk icon with a question mark on it. I remember this from OS9 days as a 'no startup disk found' alert. Neither a normal 'hard' restart or power-down/power-up has fixed it. What's going on?
I should mention this is a Quicksilver G4 running 10.3.6 and the issue I was trying to fix was the occasional defaulting to VGA screen resolution on start-up. The flashing '?' icon is appearing in VGA resolution too. Can anyone help?

Ok, following a long search of various mac fora, in which I realised that the problem is a missing system folder rather than startup disk, I discovered that booting while holding the option key down lets you choose between available system folders.. and it did! HUGE sigh of relief!
I still have the original problem(s) though.. could all this weird behaviour - VGA startup screen / blinking '?' after zapping PRAM / some (unresolved) issues with the firewire bus - point to a problem with the PRAM battery?
Thanks in advance of any reply.

IMac 27" white start up, no logo, have zapped PRAM

So, any ideas? Just a plain white screen after the start-up 'bong', no apple logo (presumably doesn't find a system folder). Pre-Retina 27" iMac running OS 10.9. Have zapped PRAM as per instructions. Nothing happening.

Take each of these steps that you haven't already tried. Stop when the problem is resolved.
To restart an unresponsive computer, press and hold the power button for a few seconds until the power shuts off, then release, wait a few more seconds, and press it again briefly.
Step 1
The first step in dealing with a startup failure is to secure the data. If you want to preserve the contents of the startup drive, and you don't already have at least one current backup, you must try to back up now, before you do anything else. It may or may not be possible. If you don't care about the data that has changed since the last backup, you can skip this step.
There are several ways to back up a Mac that is unable to start. You need an external hard drive to hold the backup data.
a. Start up from the Recovery partition, or from a local Time Machine backup volume (option key at startup.) When the OS X Utilities screen appears, launch Disk Utility and follow the instructions in this support article, under “Instructions for backing up to an external hard disk via Disk Utility.” The article refers to starting up from a DVD, but the procedure in Recovery mode is the same. You don't need a DVD if you're running OS X 10.7 or later.
b. If Step 1a fails because of disk errors, and no other Mac is available, then you may be able to salvage some of your files by copying them in the Finder. If you already have an external drive with OS X installed, start up from it. Otherwise, if you have Internet access, follow the instructions on this page to prepare the external drive and install OS X on it. You'll use the Recovery installer, rather than downloading it from the App Store.
c. If you have access to a working Mac, and both it and the non-working Mac have FireWire or Thunderbolt ports, start the non-working Mac in target disk mode. Use the working Mac to copy the data to another drive. This technique won't work with USB, Ethernet, Wi-Fi, or Bluetooth.
d. If the internal drive of the non-working Mac is user-replaceable, remove it and mount it in an external enclosure or drive dock. Use another Mac to copy the data.
Step 2
If the startup process stops at a blank gray screen with no Apple logo or spinning "daisy wheel," then the startup volume may be full. If you had previously seen warnings of low disk space, this is almost certainly the case. You might be able to start up in safe mode even though you can't start up normally. Otherwise, start up from an external drive, or else use the technique in Step 1b, 1c, or 1d to mount the internal drive and delete some files. According to Apple documentation, you need at least 9 GB of available space on the startup volume (as shown in the Finder Info window) for normal operation.
Step 3
Sometimes a startup failure can be resolved by resetting the NVRAM.
Step 4
If a desktop Mac hangs at a plain gray screen with a movable cursor, the keyboard may not be recognized. Press and hold the button on the side of an Apple wireless keyboard to make it discoverable. If need be, replace or recharge the batteries. If you're using a USB keyboard connected to a hub, connect it to a built-in port.
Step 5
If there's a built-in optical drive, a disc may be stuck in it. Follow these instructions to eject it.
Step 6
Press and hold the power button until the power shuts off. Disconnect all wired peripherals except those needed to start up, and remove all aftermarket expansion cards. Use a different keyboard and/or mouse, if those devices are wired. If you can start up now, one of the devices you disconnected, or a combination of them, is causing the problem. Finding out which one is a process of elimination.
Step 7
If you've started from an external storage device, make sure that the internal startup volume is selected in the Startup Disk pane of System Preferences.
Start up in safe mode. Note: If FileVault is enabled in OS X 10.9 or earlier, or if a firmware password is set, or if the startup volume is a software RAID, you can’t do this. Post for further instructions.
Safe mode is much slower to start and run than normal, and some things won’t work at all, including wireless networking on certain Macs.
The login screen appears even if you usually log in automatically. You must know the login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.
When you start up in safe mode, it's normal to see a dark gray progress bar on a light gray background. If the progress bar gets stuck for more than a few minutes, or if the system shuts down automatically while the progress bar is displayed, the startup volume is corrupt and the drive is probably malfunctioning. In that case, go to Step 11. If you ever have another problem with the drive, replace it immediately.
If you can start and log in in safe mode, empty the Trash, and then open the Finder Info window on the startup volume ("Macintosh HD," unless you gave it a different name.) Check that you have at least 9 GB of available space, as shown in the window. If you don't, copy as many files as necessary to another volume (not another folder on the same volume) and delete the originals. Deletion isn't complete until you empty the Trash again. Do this until the available space is more than 9 GB. Then restart as usual (i.e., not in safe mode.)
If the startup process hangs again, the problem is likely caused by a third-party system modification that you installed. Post for further instructions.
Step 8
Launch Disk Utility in Recovery mode (see Step 1.) Select the startup volume, then run Repair Disk. If any problems are found, repeat until clear. If Disk Utility reports that the volume can't be repaired, the drive has malfunctioned and should be replaced. You might choose to tolerate one such malfunction in the life of the drive. In that case, erase the volume and restore from a backup. If the same thing ever happens again, replace the drive immediately.
This is one of the rare situations in which you should also run Repair Permissions, ignoring the false warnings it may produce. Look for the line "Permissions repair complete" at the end of the output. Then restart as usual.
Step 9
If the startup device is an aftermarket SSD, it may need a firmware update and/or a forced "garbage collection." Instructions for doing this with a Crucial-branded SSD were posted here. Some of those instructions may apply to other brands of SSD, but you should check with the vendor's tech support.
Step 10
Reinstall the OS. If the Mac was upgraded from an older version of OS X, you’ll need the Apple ID and password you used to upgrade.
Step 11
Do as in Step 9, but this time erase the startup volume in Disk Utility before installing. The system should automatically restart into the Setup Assistant. Follow the prompts to transfer the data from a Time Machine or other backup.
Step 12
This step applies only to models that have a logic-board ("PRAM") battery: all Mac Pro's and some others (not current models.) Both desktop and portable Macs used to have such a battery. The logic-board battery, if there is one, is separate from the main battery of a portable. A dead logic-board battery can cause a startup failure. Typically the failure will be preceded by loss of the settings for the startup disk and system clock. See the user manual for replacement instructions. You may have to take the machine to a service provider to have the battery replaced.
Step 13
If you get this far, you're probably dealing with a hardware fault. Make a "Genius" appointment at an Apple Store, or go to another authorized service provider.

Zap PRAM with Open Firmware Password?

I'm wondering if there is any way to do this...
I have an older MacBook that had some kind of issue recently, that first prevented it from booting at all, and after resetting the SMC it would boot but the screen is black...
I remember from many years ago that there was an issue with the screen staying black that would be fixed by zapping the pram...
Problem is the system has an Open Firmware password. And while I do know what that passowrd is, it's kind of impossible to go in and disble it with a black screen...
In essense, is there any possible way I can zap the PRAM that doesn't involve psychicly guessing what I'm doing???

I'm fully aware of the key combination. The problem is when Open Firmware password is enabled, holding CMD-OPT-P-R has no effect.... The only way I know to be able to use the key combiantion is to disalbe the Open Firmware password first, then reboot and hold hte keys down.
Which is where my problem lies, as I can't zap the PRAM until I disable my Open Firmware password, and I can't go though the steps to disable my Open Firmware password until after I zap the PRAM in order to re-enable my screen...

None of the start up key combinations work (safe boot, zap PRAM, etc...)

Hi,
I can't boot in safe mode (shift -key), zap PRAM (cmd-opt-P-R), boot from CD (C) or use any other booting options. I know these may be blocked if Firmware password protection is on.
Things I've already tried:
1. Repair disk and permissions
2. I tried to boot with option key (to get the Firmware password thing). I think this only made the computer to boot again after a few seconds, but nothing else.
3. I did boot from Leopard install DVD and cheked the Firmware password protection. It seemed to be off. So, I password protected it and tried the option-boot again. But the results where same as before.
All firmware updates are installed succesfully.
So, it seems everything is blocked. Even the firmware password protection boot.
Does anyone have ideas how to get these things to work again?
Thanks
Message was edited by: Ouzone

It \shouldn't help, but have you tried plugging the keyboard into a different USB port?

Powerbook G4 will not zap PRAM

My 1.25 Powerbook G4 won't start-up when I go through the keyboard zap PRAM procedure. It starts up but I get no chime, just a blank black screen. Only when I let go of the keyboard it starts up as normal. As a result, I am unable to zap the PRAM. Does anyone out there have any suggestions?

Mark
You can try starting up into Open Firmware and resetting it from there. To start up in OF you need to press Cmd-Alt-o-f on startup and then if you see a white screen with small black text, do the following:
1. Instead of typing "mac-boot" at the Open Firmware prompt, type: reset-nvram
2. Press Return.
3. At the Open Firmware prompt, type: reset-all
4. Press Return.
If you cannot get to the OF screen then perhaps try resetting the PMU first.
Message was edited by: EddieC

White screen (of death), zap pram doesn't work

Four year old MacBook pro, running 10.6.something, this morning I touched the cursor and the screen went wonky (plaid crisscrossing), then white nothingness. Out of AppleCare, four hours from a store. Zap pram did not changed anything. Time for a shotgun?

Thank you for your replies...
jmrmb80 - Yes the device is still recognized by the Desktop Manager. I reloaded the OS on it this morning and the App Loader says it was successful - but on reboot the white screen loads and thats it.
billrobinson - I haven't dropped the phone since I bought it. I wish I had b/c then I could blame it on something. My friends drop their phones all the time, spill stuff on them etc.... and I do nothing - and my phone blows up

Can't Zap the P-RAM , Can't start from an installer disk with the C-Key...

Can't Zap the P-RAM , Can't start from an installer disk with the C-Key... or The D-Key for Apple Hardware test or run with the shift Key in Safe Mode!!!
About a week ago I started to have problems with the Mac after 10.5.6! First the Mac after shut down would restart on its own in 10 to 15 minutes. I read in various forums about some of the 10.5.6 problems. I did a clean reinstall where the Mac created a previous system folder. After this suddenly mail, I-Chat as well as some other programs would open, then close immediately! Since I did not have things backed up because I didn't have a large drive, I dragged my files and apps to another drive and reformatted the drive zeroing out all data and did a fresh new install then brought in the combo 10.5.6 update.The Mac is running correctly but I can't Zap the P-Ram, startup from the Mac OS X installer Dvd with the C key or run Apple Hardware Test with the D key or boot in safe mode with the shift key. I can boot any of the Bootable disks from the start-up Disk in Preferences.
I went over this with Apple and they suggested I run the Apple Hardware test. It won't run on this machine because I can't boot it with the D- Key. I ran tech Tools and every single thing checks out OK! This Mac has worked great since I got it in I believe Feb or March of 2007.

Make sure that you don't have firmware password protection enabled. It will prevent some boot key shortcuts from working, like clearing NVRAM, etc. You can disable firmware password protection by booting off the OSX DVD and loading the utility.

Zapped PRAM, now no gray screen

I'm running OS X 10.6.3 on a late 2009, 3.06 GHz Intel Core 2 Duo iMac with 4 GB of RAM.
This one is actually fairly self-explanatory and the cause is easily identified: hoping to fix some other technical difficulties I was having, I zapped my PRAM through the standard 'Command + Option + P + R' method and now whenever I boot up, I don't get the standard gray screen telling me how things are going -- even when holding down option. Instead, everything is pitch black until OS X fully loads and I get a flash of blue. Even when holding Option to bring up the list of boot disks, I'm staring at a screen as black as midnight (despite the computer otherwise responding correctly) until I press enter and blindly tell it to boot Macintosh HD.
I would be grateful for any assistance.

This problem still exists! Zapping PRAM this way and that way change nothing, I'm still getting black screens instead of gray as I'm booting up, until things are fully booted. It's as though the default monitor settings have been screwed up and are only becoming fixed when it boots up enough to check what my desktop actually wants.
So this is some sort o' bump.

Can't zap PRAM

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