Some times Ubuntu darkens the screen a lot and I can't click on anything.

[cheater87]

What could be causing this??? Its very annoying.

[Searching_ _ _]

It's an Omen.

You should stop using Ubuntu.

[Arup]

That means some program is crashing.

[cheater87]

:*( But my windows BSOD's me today.

[Eice]

-{ Quote: "That means some program is crashing." }-
Doesn't that apply only for the crashing program, and not the whole screen?

[Arup]

-{ Quote: "Doesn't that apply only for the crashing program, and not the whole screen?" }-

True, although in case of root access the password window pops up darkening all in background.

[SpikeyB]

-{ Quote: "What could be causing this??? Its very annoying." }-What do you do to get out of it? Do you have to switch off the pc or something else?

[Ocky]

Probably means Ubuntu is too busy to handle any other processes - just wait
till it's done.

[cheater87]

yea I had to shut down the laptop. I'll wait next time.

[lotuseclat79]

When I bookmark a webpage it darkens for about 10 or more seconds after selecting the New Folder button (I have lots of bookmarks).

The only thing to do is to wait in this case.

-- Tom

[Nick Rhodes]

I get this, it is when something running via GDM (Gnome Desktop Manager) is taking its time.

If your machine does not respond and you suspect it will not in the near future, your first action should be a ctrl-alt-backspace.
If that fails to restart X (and therefore your desktop manager), you should try changing to a different TTY (eg ctrl-alt-f1) and login and issue "killall Xorg" with root privalidges (eg su or sudo). Switch back (usually TT7 (ctrl-alt-f7)) so see if your desktop is still hung (you should be at the login screen).

If that fails then you need to reboot your machine, issue the command "reboot" or "shutdown -r now".

Cheers, Nick

[Ocky]

Something else to try...

"In case of a freeze where you cannot do anything, simply press Alt+PrintScreen+R+E+I+S+U+B, keep in mind that the underlined keys must be kept pressed through the rest of the sequence AND that you will need to keep holding the sequence keys for a small period of time before going to the next one so that their actions can be carried out properly (For example, hold the R key for about 1-2 seconds before moving on to S). If the sequence does not work at first, then increase the time period between each sequence key press and try again.

If anyone requires a good way of remembering the sequence R+E+I+S+U+B, just remember “Reboot Even If System Utterly Broken”.

Raw (take control of keyboard back from X), tErminate (kill -15 programs, allowing them to terminate gracefully), kIll (kill -9 unterminated programs), Sync (flush data to disk), Unmount (remount everything read-only), reBoot.

NOTE:- This keystroke does not work in the event of a kernel freeze as the keystroke sequence depends on the kernel in order to unmount and make the required steps before the restart."

[Mrkvonic]

Magic keys won't work if they're not enabled in kernel.
And I would not advise something like that to new users ... :)
Mrk