USB drive spontaneously switches to read only

This has happened to me twice now. I have inserted a USB drive (formatted for FAT32) into Macbook. The USB drive has been fine for a while on both my Macbook and my Windows 7 computer. Then suddenly and spontaneously switched to read only while inserted into Macbook, without any action on my part. I have OS 10.8.5 installed on my Macbook Air. Anyone else have this problem?

Does your USB drive have a lock switch like SD cards? I have found that sometimes my SD cards will show the same behavior, it is because the lock switch got moved during insertion.
Also usally just ejecting and plugging in resolves the problem.
What is the brand and model of your flash drive?

Similar Messages

External OS X formatted drive keeps switching to Read Only

Since completing the upgrade to 10.7.2, my generic external eSATA drive case holding a Caviar Green drive decides randomly that it should be read only, despite having been formatted as OS X Journalled. Disk utiliy says that permissions have errors but I cannot repair them. It also says taht the drive is not journaled which it was set up to be.
Using Get Info shows system as Read & Write, wheel and everyone as Read Only. Unlocking with the admin id does not allow changes to be made to the Read Only settings and consequently my Carbon Copy Clone update fails every time as did the Super Duper method I was using previously.
The point of an extra backup is to keep it up to date, not to have to format the idiot thing every couple of days.
It happened again today and given the lack of any kind of solutions found with Google, I tried to add an authorized user. I clicked the plus sign and selected my own id. After accepting, the id was not added, nor was the Administrator group when I tried to add that. However for reasons I do not understand I was now able to change wheel and everyone to Read & Write. I was able to get CCC to do its update but I continue to have issues making the privilege correction stick.
Once I was able to filter out all the dreck about NTFS mounts, I discovered that A LOT of users were complaining about this happening and all the "helpful" advice was to reformat and start over. That's not particularly helpful as it does not fix the problem or prevent it from happening again.
I don't know if the workaround I discovered will work again and I suspect that since both Super Duper and CCC actually call the open source service called rsync, there may be a bug in rsync in OS X 10.7
Anyone know the root cause and the permanent fix?
Thanks!
Ross

More info. It's not RSYNC. My LaCIE USB3 drive that has worked flawlessly as a RW volume decided that it is Read-Only. My trick above does not work. What a pain in the butt this is, and no answers from Apple as to why this happens.

My external drive keeps setting to read only, why???

Periodically a 1TB external drive suddenly switches to read only and won't let me save edited documents to it any longer. It shows as read and write for my access but still won't accept written items. I'm curious as to why. It's getting a lot of files but still has significant space. Is this an address space issue? Has anyone else encountered this on their Mac?

The drive is malfunctioning.

I have an external hard drive but it is read only on my macbook.

I have an external hard drive but it is read only on my macbook. I have tried my friends which works on his macbook but this is also read only on mine. Do I need to change any settings?

Here's my lo-tech solution (if you have Parallels) to this frustrating problem:
Eject your hard drive.
Unplug (USB) your hard drive from the MAC .
Start Parallels.
When Windows has started, plug your drive back into the MAC.
You should get a little screen asking if you want the drive to be utilized by MAC or Windows. Select Windows.
Use Windows to copy your files over to the hard drive.
This is less than ideal and not a long-term solution, but I was afraid of attempting any reformatting since I have many files on my hard drive.
Just remember that Windows has to be running first, before you plug in your hard drive.

EXFAT formatted USB stick - sharing permissions wrong - Read Only - Cannot Reformat - Help please!

EXFAT formatted USB stick - sharing permissions wrong - Read Only - Cannot Reformat - Help please!
Hi.
Having various problems with a USB stick that is formatted in EX-FAT.
It was working fine for a long period.
Yesterday I lent it to a friend to put some things on it.
Now when I try and work on it, I get messages like this.
Mac OS X can’t repair the disk “Disk Name"
You can still open or copy files on the disk, but you can’t save changes to files on the disk. Back up the disk and reformat it as soon as you can.
It will also randomly eject the drive.
I have tried to reformat it multiple times, in mac and windows.
[I have never used it in windows previous to this occasion of needing to reformat].
In windows, it crashes the disk when I attempt to format with disk manager [I attempted this due to advice in an internet article].
In Mac , I cannot even try to reformat it, because for some reason the permissions on the USB stick have been set to "read only" and I cannot find any way to change them to read-write, or full permissions, or whatever is appropriate.
I have tried "erase" disk in disk utility. I know how to do a full reformat, but it simply will not allow me to do so.
All the options are greyed out.
Does anybody have any information or links they can point me to?
I've been searching around.
Thanks very much in advance for any advice received.
Running latest mountain lion , 10.8.4, and windows 7 through VMware fusion.

Start over:
select the drive > select the Partition tab > select 1 Partition
select Option > select GUID Partition Table > select OK
name it > click the Apply button > then lastly click Partition

External hard drives suddenly changed to read only

Three of my external hard drives suddenly changed to read only. These hard drives have been working on my macbook pro for months. When I click on get info 'read only' shows up and there is no lock icon nor is there a window that shows name | permissions, also in disk utility the 'verify disk premissions', 'verify disk', 'repair disk', and 'repair disk premissions' buttons are ghosted and I can not select them. I have not made any changes to my computer and I have read many other posts and have not been able to find a solution.

About a hundred times with no luck. Some of my research is leading to Western Digital, there may be a problem with the drives' 'smartware' software. I've been using this drive for months and I never used the 'smartware', but I tried it anyway with no luck. I just remembered that four days ago I had this drive plugged this drive into an Iomega wireless storage device and it seemed to work fine. Now the wireless storage device can't find the drive at all. I just need to know if there is a way I can change the permissions back to read/write, otherwise I will have to buy another drive and transfer all the data to the new drive and re-formatt the wd drive.

I purchased a IMac in Feb later I added a Seagate ext. hard drive. On April 29 I received an errors that the ext. Drive may be a read only and not backing up files. I'm unable to check disk permission or correct errors. Help would be appreciated.

I purchased a IMac in Feb later I added a Seagate ext. hard drive. On April 29 I received an errors that the ext. Drive may be a read only and not backing up files. I'm unable to check disk permission or correct errors. Help would be appreciated.

Click on the hard drive on the desktop, then File > Get Info. What does it say about permissions? If this is just a data drive you may want to consider "ignore ownership on this volume".
Otherwise I can only say I have not been reading good things about Seagate drives recently. I have some of their rock-solid ones from about 10 years ago (still running well), but now...?

[solved] External drive automatically mounted as read-only

Hi folks,
I have a strange issue with an external drive automatically mounted as read-only whenever I plug it to my laptop :
[sclarckone@archLaptop ~]$ mount
/dev/sdb1 on /run/media/sclarckone/dd type ntfs (ro,nosuid,nodev,relatime,uid=1000,gid=100,fmask=0177,dmask=077,nls=utf8,errors=continue,mft_zone_multiplier=1,uhelper=udisks2)
And I can't remount it as read-write :
[sclarckone@archLaptop ~]$ sudo mount -o remount,rw /dev/sdb1
mount: cannot remount /dev/sdb1 read-write, is write-protected
But of course, I'm able to mount it as read-write on other operating systems.
I have udisks and udisks2 installed on my system. I also belong to the storage group so I thought I could mount a filesystem as a normal user but I can't :
[sclarckone@archLaptop ~]$ mount /dev/sdb1 dd/
mount: only root can do that
I don't know whether it is relevant to this problem, but I have systemd and polkit installed as well... Does anybody has an idea of where the problem could come from ?
Thanks for your help !
Last edited by sclarckone (2012-12-13 21:45:04)

Check out following file :
/usr/share/polkit-1/actions/org.freedesktop.udisks.policy
Look for mount a device and It should have configuration like :
<action id="org.freedesktop.udisks.filesystem-mount">
<description>Mount a device</description>
<description xml:lang="da">MontÃ©r en enhed</description>
<message>Authentication is required to mount the device</message>
<message xml:lang="da">Autorisering er pÃ¥krÃ¦vet for at montere et fil system</message>
<defaults>
<allow_any>no</allow_any>
<allow_inactive>no</allow_inactive>
<allow_active>yes</allow_active>
</defaults>
</action>

My External Seagate Hard drive just changed to read only

my External Seagate Hard drive just changed to read only on its own?
I went to get info and scrolled down to the Sharing and Permissions
But there is nothing there but a greyed out : You can only read
There are No boxes to check or uncheck, No options to change to read and write, No name of owner or ignore ownership box. NOTHING ELSE IS THERE
HELP!
I have recently upgraded to Mountain Lion and am having other problems as well

Click on the external HDD icon COMMAND+I. You should see a display such as this:
You should be logged on as the administrator. Click on the lock icon. It should open and allow you to make the required changes.
Ciao.

USB hard drive is set to read only?

I'm am very new to Mac (my first one). I plug my USB Seagate drive into the Mac and it reads it fine, but says everything is read only. How do i set it up to allow the Mac to modify the files? Does the hard drive have to be reformatted to a Mac OS and/or is it possible to use the same hard drive on the Mac and PC. I have windows XP Pro SP3 installed using VM Fusion as well.
I have done a lot of video editing Windows based and very rarely moved the files to my PC hard drive. I have to assume you can do the same with Mac, however I have been able to figure out how to do this in iMovie 2009.
Thanks in advance,

BRDVPRA,
Your external drive is undoubtedly formatted as NTFS. As you already know, your Mac can read this format, but it cannot write to it. There are some third-party shareware applications that will allow your Mac to write to the NTFS volume; search for these on versiontracker.com, if you want to give this a try.
The native Mac format is HFS+ (Mac OS Extended), which cannot be read natively by Windows. Again, there are third-party solutions for this (specifically, a Windows app called "MacDrive," also available on versiontracker.com).
The only format that will allow reading and writing from both OS X and Windows is the FAT-32 format (called MS-DOS in Disk Utility). This format is older, and less compatible with modern file formats. For example, it will not support files larger than 4 GBs.
The question that needs answering is whether or not you will using this drive cross-platform, or whether it will be dedicated solely to OS X. If the former, you'll need to use either the FAT-32 format or some third-party solution. If this drive will only be accessed from OS X in the future, you should copy the data, format it as HFS+ (Mac OS Extended), then return the data to it.
Scott

External Hard Drives Changing Permissions to Read Only

Three of my USB external hard drives have suddenly changed to read only. One of the times I was trying to transfer/back-up the files from one drive that had changed to read only to another external. Suddenly the second drive changed permissions. Then after plugging a third external, that drive changed permissions. They all were working perfectly fine with my computer and I have only been using them on MACS. Any explanations? Could there be something wrong with my USB ports? Is it possible to have a virus of some sort?
Thank you!

In disk utility I had a look. I cannot verify or set permission (greyed out). The data coming back from info. How can I change this??
Name : FUJITSU MHZ2320BH G1 Media
Type : Disk
Partition Map Scheme : Master Boot Record
Disk Identifier : disk2
Media Name : FUJITSU MHZ2320BH G1 Media
Media Type : Generic
Connection Bus : USB
USB Serial Number : 560A48A291F9
Device Tree : /PCI0/EHC1@1D,7/@3:0
Writable : Yes
Ejectable : Yes
Mac OS 9 Drivers Installed : No
Location : External
Total Capacity : 298,1 GB (320.072.933.376 Bytes)
S.M.A.R.T. Status : Not Supported
Disk Number : 2
Partition Number : 0
Name : NieuwVolume
Type : Volume
Disk Identifier : disk2s1
Mount Point : /Volumes/NieuwVolume
File System : Windows NT File System (NTFS)
Connection Bus : USB
Device Tree : /PCI0/EHC1@1D,7/@3:1
Writable : No
Universal Unique Identifier : C7B58C48-D6BC-4078-9DAE-CB125901A4D6
Capacity : 298,1 GB (320.070.288.384 Bytes)
Free Space : 127,1 GB (136.438.530.048 Bytes)
Used : 171,0 GB (183.631.757.312 Bytes)
Number of Files : 85.578
Number of Folders : 0
Owners Enabled : No
Can Turn Owners Off : No
Can Be Formatted : No
Bootable : No
Supports Journaling : No
Journaled : No
Disk Number : 2
Partition Number : 1

External Hard Drive changed permissions to 'read only'

I have been searching everywhere for a solution to this with no luck, so I figured I would start my own post and see what comes of it.
Computer: iMac Intel 24" /3.0ghz/4gb ram/1TB WD hard drive
External Drive giving me issues: Western Digital 1.5TB (has been formatted for Mac)
I recently installed a new main hard drive into my iMac after the original one began to die. I have an external drive that I had been using for achiving files for a long time, with no issues at all. After I installed the new drive, it has suddently become 'ready only' - thus, I cannot write to the drive at all, but can pull information off of it.
When I go to 'Get Info' and down to the permissions section, it is completely 'greyed out' - I can't change or click anything. It reads:
sckenyon (me): read & write
staff: read & write
everyone: ready only
Which is normal, but given that I should have writing priveledges, shouldn't I be able to change those permissions? Or that I should have writing permissions since it shows that I should have them?
I have tried some commands in terminal under other discussions, but I just get a statement that says the volume is 'ready only'.
I have tried Verify Disk in Disk Utility - doesn't do anything, just tells me the disk is OK. I have no option to repair permissions - they are greyed out.
So, can anyone help me out here? I'm at a complete loss! I'm not a complete noob at this, but I am definitely not an expert. I'm capable of following terminal commands if that's what it takes, but I do not want to format the drive if I don't have to (it's already formatted for Mac, so I don't see why I should have to).
Thank you

The problem may be an erroneous flag for the volume of the external drive that puts it in read-only mode. When I had a similar problem, the following steps corrected it.
1. Open Disk Utility and Verify the Volume.
2. If the verification shows that the volume is OK. If so, run repair disk. If the verification does not shaw that the volume is OK, STOP. Copy the drive immediately to oanotehr drive before proceeding. Failure to do so can result in permanent data loss.
3. After the repair function completes, close Disk Utility and start Terminal. It is located in the System Utilities. Type in the following command:
sudo chflags nouchg /Volumes/[Volume Name]
For example, assume your external drives are named Mary X where X is a sequential Arabic numeral. The command line for one of those volumes will be "sudo chflags nouchg /Volumes/Mary\ X" where X is the drive number. You will be prompted for your administrator's password. Note that when you type in the password, it will not be echoed in the terminal window for security reasons . Press "Return"
If your experience is similar to mine, your external drive will no longer be in read-only mode. Hope this is helpful.

Folders automatically switch to read only

Some folders on my mac automatically cahnge their permissions from read & write to read only, which means whenever I want to edit a document I have to enter my password and reset the folder permissions.
It just happens randomly, I am an Admin on the computer and the only user.
I have also repaired the disk permissions to see if that will fix it but it still happens.
Any help would be greatly appreciated.
Thanks

You may need to rebuild permissions on your user account. To do this,boot to your Recovery partition (holding down the Command and R keys while booting) and open Terminal from the Utilities menu. In Terminal, type: 'resetpassword' (without the 's) and select the admin user. You are not going to reset your password. Click on the icon for your Macs hard drive at the top. From the drop down below it select the user account which is having issues. At the bottom of the window, you'll see an area labeled Restore Home Directory Permissions and ACLs. Click the reset button there. The process takes a few minutes. When complete, restart.
http://osxdaily.com/2011/11/15/repair-user-permissions-in-mac-os-x-lion/

USB flash storage mounted as read-only filesystem

Hello all,
I'm new to Arch Linux and trying to migrate all my works to arch. Installed KDE, GNOME3, and hardware drivers successfully But I have problems with USB flash disks. When plugging a usb device, system mounts it as a readonly filesystem. so I can't change its contents. It always happens to my flash disk, but flash disk of my friend is ok!
I tried to mount manually with super user access, but no hope. It says:
[root@myhost soroush]# mount /dev/sdb1 /mnt/
mount: warning: /mnt/ seems to be mounted read-only.

roygbiv wrote:Maybe you can post your /etc/fstab?
# /etc/fstab: static file system information
# <file system> <dir> <type> <options> <dump> <pass>
tmpfs /tmp tmpfs nodev,nosuid 0 0
/dev/sda2 / ext4 defaults 0 1
/dev/sda3 /home ext4 defaults 0 1
/dev/sda4 swap swap defaults 0 0

Hi all not sure where original request went but as a new apple user I have external hard drives that are now "read only" and I can't change or save documents. Went to Get Info and this did not help. Can anyone assist with solution, thanks.

I am a new user to apple and have external hard drives from previous computers. I have many documents I can no longer access and change as they say the drives are read only. How do I change the read only to read and write etc for these external drives. I tried Get Info but this did not assist. Thanks.

Hi,
Google is your Friend
10:18 PM Sunday; February 12, 2012
 iMac 2.5Ghz 5i 2011 (Lion 10.7.3)
 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb (Snow Leopard 10.6.8)
 Mac OS X (10.6.8),
"Limit the Logs to the Bits above Binary Images."  No, Seriously

USB drive spontaneously switches to read only

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