Thanks go out to filologen.

I attempted to back up my 900, using the backup utility on the device. The process apparently failed at some point, and I began getting a "memory is read only" error. filologen's tip above appears to have taken care of the problem.

Ok, same happened to me.
I tried to download files (torrents) with Transmission. For some reason, the whole app froze so totally that I had to reboot the whole device. After this, I restarted the Transmission and got the same "Read-only file system error..".

I then went to Xterm, gainrooted and tried to remove the files with no luck. I also tried via the file manager with the same result.

Next step was to reboot the device again - still no luck with the above steps.. I then rebooted the device once again after which I was able to remove the files using the file manager.

I _think_ this might have something to do with the fact that
1) You first have files downloading in Transmission
2) You then for whatever reason reboot the device
3) --> The files you were downloading are marked as read only
4) It requires not one, but two reboots to fix!

This might be a b*tch to reproduce, so if anyone else has had similar experiences please comment so we can open up a bug for this..


EDIT: Might not be related to Transmission at all if there are similar problems with backup also..?
//Laiska

I had this issue with a download in gPodder. It seems the vfat is very fragile on the Maemo. If there is any issue, the system switches to read-only mode.

I fixed it as root by unmounting the MyDocs partition, then doing a fsck -a on the partition. Then a reboot, but a mount of MyDocs should do too.

Ok, today this problem came to me too. I've opened video in media player, which caused N900 to crash so hardly that it rebooted itself (no error message, no application freezing, just instant reboot without any question).

When it came back to life, everything seemed to be allright and worked properly. Then i tried to delete folder located in /Music/some_artist/ - voila, simple "Operation failed" error message. I went to root with filemanager and noticed that whole "Music" folder disappeared, but because no space was freed, the files (about 10GB in 2500 files) have been somewhere. When I listed files in console, I've noticed folder named "._ďŞ" in MyDocs - probably my original "Music" folder, but because of the weird characters in it's name i was unable to list anything within.
Now my favorite part comes - whole .documents directory war read-only, despite it's permission were set to 0777. That means no document editing, no camera photo or video saving etc.

So i tried the procedure mentioned here:

1) unmounted MyDocs when logged to console as root
2) ran fsck -a on /home/user/MyDocs and waited (for about 70 minutes)...

When completed, I've rebooted phone and everything seemed fine, except that my Music folder (which appeared back in root by the way) was empty and all files from that folder were placed in root and renamed (=useless). So the result? All music gone.

Well, I'm pretty sure that this isn't problem with certain application, but with the filesystem itself, which seems to be quite unstable. For me the only solution how to avoid this in future is to repartition inner memory to ext3 while leaving FAT32 on memory card to keep the camera working... Nice.

What is unmounting? How do you unmount?
Can this process be done without connecting to a pc?
This is a real issue.. Has anyone found any other solution since?

Follow filologen's instructions, works for me and I have been dealing with this since I got the device.

After transferring files it must be important to properly unmount device. I used to just pull the cord when I thought things were clear, but no more...

the system is indeed very fragile. lots of people seem to have this problem. a few weeks ago i copied a file to my n900 memory from pc. and for some reason it crashed half way. after that the whole phone was read only. There should be a more easy way to get the system back on its feet. like an option where you need the phone security code to get things back how they were.

Not sure if my error is the same as the OP but thought it close enough to post on this thread, apologies if not the same....

Plugged my N900 into the USB to draw power for charging. Clicked on the Mass Storage Device option then I end up with the following warning message across the middle of the screen:

When I open file manager on the device I see that the memory card Video directory has a question mark for an icon and a size of -1KB reported. My suggestion is therefore that the filesystem on the memory card has been corrupted.

Any thoughts on this one?

Ok peeps, problem appears to be solved, it was indeed a corrupt filesystem on the memory card. For the person asking about how to fix this on Windows it is possible (as in the office so that's all there is). Just simply right click on the drive and tell Windows to scan for errors. Takes forever but did seem to do the job in my case.

Did the try for me thanks.

1) Backup
2) Copy Backup somewhere else than on the phone
3) Reboot
4) It found the problem in less than 1 minute !