You can search for this bug and it seems like it may be related to ecryptfs and is many years old.
The symptoms are that you return to the computer and the screensaver was active or the screen was asleep/black and it doesn't seem to come back. But you check by SSH the computer is running fine and are frustrated you'll lose your running programs and have to reboot.
There is a simple solution:
Ctrl + Alt + F1
Ctrl +Alt + F8
Ba........
This is not the normal "black screen"issue and I was shocked to eventually find out why. The normal advice of reconfiguring Xorg didn't work. Even booting into "Recovery Mode" did not help.
Here is the short end of the stick that fixed it:
sudo apt-get install mdm mate-desktop-environment
Yes you got it right, mdm and the mate-desktop-environment / gnome were somehow uninstalled. This must be whe........
You can download the latest Sea Monkey releases here and 64-bit issues are a thing of the past now:
It's a little tricky if you are running a 64-bit OS which most people will be.
The weird thing is that the Seamonkey website for Linux seems to only provide a 32-bit download.
seamonkey-2.49.2.tar.bz2
Seamonkey is still provided as a tar.bz2 which you need to extract and run manually.
First........