USB flash drives umount / freeze [SOLVED]

[fotonix]

I've been running LM17 Cinnamon 64b across all our home machines without problems. Today my one child's computer refuses to behave when a USB flash drive is inserted. Their machines are set up that I am admin and they are just users (cannot install, change, etc, etc).

What has been observed. The USB device is recognized, though only a generic icon is shown on the desktop, not the usual one from autostart.inf. A message then flashes near the bottom of the screen stating the drive is now DISmounted successfully. From here the desktop hangs (power off required), or hangs after VLC tries to play the ?binary?

Wierdest part - this happens only in the unprivileged user account, my admin account works fine - USB mounts with correct icon and acts normal. No strange permissions, and I've tried this with more than one USB and different capacities. Same mystery - crashes up on the child's account, works fine on my account and on other machines.

Appreciate any clues from the resident genuises and gurus as to where to begin hunting down and solving the problem.

[Buzzsaw]

Something's obviously gone wrong with the user account in question. Deleting the account and then creating a new one to replace it would probably resolve the problem.

[fotonix]

Update / upgrade to 17.1 seems to have cleared it up. My kids have this infuriating habit of not telling what happened in time for action. Sometimes years later they spill facts that could have been useful at the time. So finding out if my daughter did something wierd or unusual on her account - no telling - maybe in 2028 if she remembers. sigh....

[fotonix]

Sorry folks - after checking my daughter's account in person, the problem is still there. It seems to only affect USB thumbdrives. All works 100% from my account, the only difference is mine is admin/root and hers is not. However, this same setup works fine on my son's almost identical system.

What the user sees on inserting a drive:
"DeviceDescriptor has been connected" and a second later "DeviceDescriptor successfully unmounted" (gray info pop-up bars on desktop)

Checking in /media:
drwr-x---+ myadminacct
drwr-x---+ daughteracct

Identical permissions, where the USB mounts as /media/UserAccount/Serial-Number

I checked with the 'mount' command and get the same data in my account and my daughter's (aside from uid and gid of course):
/dev/sbd1 on /media/UserAccount/Serial-Number type vfat (rw, nosuid, nodev, uid=100X, gid=100X, shortname=mixed, dmask=0077, utf8=1, showexec, flush, uhelper=udisks2)

Symptom - I can get this out of 'mount' AFTER the system said "DeviceDescriptor successfully unmounted". The icon remains on the desktop, but if you click on it, the system freezes up - sometimes recovering, but mostly its power-off, power-on time.

In trying to understand the mechanisms I have searched the interwebs. Examples:
http://www.techsupportalert.com/content ... dition.htm 2/3 down: Automount / Manual Mount
and many very useful others which I can't find right now.
One of them listed a bunch of packages that one can pick and choose from to automount - but what makes LM's automount tick (which one of the 7)?
One of them had a useful diagram of the automount layers of command, but seemed a few years old.

I have tried to flush out some "gunk" in $HOME/.local but this had no effect. I really suspect the problem (and solution) are lurking in some dot-hidden file in the user account. Finding it is the current challenge. Creating a new account seems a bit extreme and I might copy the problem along with other data - and I'm not wanting to sit and copy one file at a time, relogin, test, next file (see you next millenium).

Most "help" threads cover the general case of automounting the drive (system wide).
http://help.ubuntu.com/community/Automa ... Partitions
or you get really ancient, creaky stuff from 2003 (wow, 64MB CF cards - museum-level items)
http://www.vanemery.com/Linux/USB-Compact_Flash.html
or a totally confusing minefield of information overload (they need to learn about shorter, more humane URLs)
http://unix.stackechange.com/questions/ ... eplacement

At this point, I can't see the wood for trees in the forest.

[fotonix]

Final solution - feels like Windows 95 again. [SOLVED by RE-INSTALL]

I had some hours spare to revisit the problem laptop and account. By now even DVDs would not play from my daughter's account, but everything would work just fine from my account. I opened Nemo as root, made a backup of her home folder. I then removed the account, restarted, recreated the account. It now didn't accept ANY external media - the external backup HDD, a DVD, or a USB stick. The icon would show up on the desktop though (not just freeze as earlier), but a pop-up would follow: "/media/user/device is not a folder".

Ok, I know when I'm bested. I went back to my account, backed up up my home folder and also used the Mint Backup tool to preserve the installed software selection. Sigh - went back to Win95 days with an OS re-installation - hauled out the LinuxMint 17.1 Cinnamon 64 DVD and started from blank metal. At least that is done in 15 minutes! I then let updates run their course. Went into my account and restored the software selection via Mint Backup. Wow, this thing works exactly as advertised! It was quick and made the whole thing painless. I then restored my own home folder files, getting back things like my local homepage and FF settings. And then finally I created my daughter's account and restored her home folder files. 2 hours of my day.

And? ... it now all works as it should and we have most if not all the files and settings back.

[Buzzsaw]

Ah, good. Reinstalling is my preferred method when something goes wrong. It's a pity you can't find out what your child did to break it.