I recently upgraded my tablet, an LG G Pad 8, from Android 4.x to 5.0.2, and now my SD card won't mount on my 'User' profile, only the 'Owner' profile. The SD card worked fine on both before, and it's still working for the Owner and on my PC. On the User profile, it won't show up in storage or detect at all when I insert it, but for some reason I will still get a notification every time I remove it.
I'm not sure if this a bug or if I'm just missing some new security feature that's restricting the SD card to the Owner, or something else I'm doing wrong. I haven't tried reformatting the card yet, if that would help. I'm not very experienced with Android.
I tried looking it up, but I mostly found problems involving the SD card not being detected at all, except for this one unaswered question:
http://android.stackexchange.com/questions/62709/mount-external-sd-card-for-the-secondary-user
but that was for Android 4.2.
Any suggestions?

My experience shows that android mounts the SD card a little hidden and tucked away. Under /mnt/extsd/ or /mnt/ext/sd, something like that. I usually can't access it without a file manager installed (which i do).

That should be where it is, but its not showing up in file manager on the User profile, either.

Try ES File Explorer. It's vastly more useful than what typically comes with Android, and the homepage includes a direct link to wherever the external SD card is.

Other than that, sounds like it's an Android problem of some kind. Perhaps resetting the tablet will help?

It generally seems to me that each new version of Android makes external SD cards more useless than before. I'm guessing this is a deliberate strategy in order to sell more expensive units with more memory, since they can charge much more for those than for SD cards.

Hmmm what is the SD card formatted to? Maybe it needs to be freshly reformatted to Fat32? That's exactly what i use! Although some of the newer versions i was iffy on so i use an older version. Great for starting up videos, music, pdf files, accessing network drives, the works!

It's already in Fat32, but I'll backup and try a fresh reformat and see if it helps when I get home, currently typing from the tablet at the moment.

I just tried ES File Explorer, really nice app, but it didn't help. It only detects the internal storage. I've tried restarting the tablet with card removed, unmounting the SD card from the Owner profile, nothing seems to work. It's like it doesn't exist on the User profile.

It might not matter if it's already Fat32. If the filesystem was left in a corrupted state it just might not mount it, and since Android is a cut down version of Unix/Linux, it has no commandline or tools for fixing the problem while you're at the tablet, you need to fix it on another computer.

Also to note, i noticed one of the Fat32 partitions used for users was unable to copy normal files anymore (this was after copying say 400 files and deleting them over a few weeks, like music files, pdfs, videos, etc), be it for installed apk files or personal data, the only fix i had was to reset to factory default.

I really wish the OS wasn't so bare bones.