Comment 143 for bug 1311316

I updated to Unity 7.2.4 (using the ppa described above) and still have the problem. It happens quite regularly, but not predictably.

Ubuntu version:

LSB Version: core-2.0-amd64:core-2.0-noarch:core-3.0-amd64:core-3.0-noarch:core-3.1-amd64:core-3.1-noarch:core-3.2-md64:core-3.2-noarch:core-4.0-amd64:core-4.0-noarch:core-4.1-amd64:core-4.1-noarch:security-4.0-amd64:security-4.0-noarch:security-4.1-amd64:security-4.1-noarch
Distributor ID: Ubuntu
Description: Ubuntu 14.04.1 LTS
Release: 14.04
Codename: trusty

Dual monitors. The password box only appears on the monitor that is "active" as defined by where the mouse pointer is. When it stops working the dialog box has no text-entry field. I can switch the dialog from one monitor to the other but the text-entry field for the password will never appear.

I can SSH into the machine, issue "unity --replace" and it will cause the password prompt to reappear. I can then issue "unity --reset-icons" (but only after entering my password and finding an open terminal windows - this doesn't work from the SSH session) to get the UI to the desktop working again. If there is no open terminal window I am out of luck - there is no keyboard interaction with the desktop and there are no controls available to open a window with a mouse). I have to fix all my terminal windows which have moved to the upper left of the leftmost screen but I'm OK.

The "unity --reset-icons" command hangs and if I ctrl-c the terminal session or stop that process I lose the UI again. But as long as that terminal session stays open things work. It enter the error state again (no password field in login dialog) after I've done this.