In 13.04, whenever I connect an Android device, one of three things happens:

1 . It mounts successfully (maybe once out of 3 attempts)

2 . It fails to mount with the following error message:

Oops! Something went wrong.

Unhandled error message: Unable to open MTP device

3 . This one occasionally happens:

Unhandled error message: No such interface `org.gtk.vfs.Mount' on object at path /org/gtk/vfs/mount/1

Regardless of activity (even when successfully mounted) it will continuously spam the following error message:

Unable to mount SAMSUNG_Android

Unable to open MTP Device '[usb:003,00x]'

where x seems to be an arbitrary number below 10 and continues counting up with each new error message until the device is unplugged.

I've also just noticed that even if it mounts successfully, it unmounts after about 30 seconds and starts spamming the error message above. The Android device is unlocked, always on and fully charged. ADB seems to function normally.

Any suggestions?

Further info: this happens on both a stock Samsung S3 and an Xperia Arc S running a custom AOSP based ROM. I've also tried the steps outlined in this Stack Overflow answer, but the problem persists.

UPDATE: After doing a dist-upgrade (May 8th 2013), the Xperia Arc S on AOSP ROM now mounts and behaves normally. The S3, however, still behaves as described above.

UPDATE: After careful observation, ABD does not, in fact, behave normally. If the error message above appears while sending an app to the device, the attempt is aborted with an error message saying that the device is unavailable.