Why is Photoshop acting strange? Some things just aren't working right.

[Steve]

It could be a corrupt preferences file.

If you've made a lot of changes to the Photoshop's default settings you may want to rename it to see if that's what causing the problem.

You could locate the file and rename it.
When you restart Photoshop a new preferences file will be created with the default settings.

Here are the locations of the Preference files in the last 4 versions of Photoshop.
This information was originally posted by one of our members, Paul MR.

Preferences files vary by name and location for each version,
with each version storing its own preference settings in a different set of files.

You may need to do some research on how to locate the preferences file for your Operating System and your version of Photoshop.

A few of the clues that the Preferences file has gone bad are:

Freezes and crashes.
Unusual tool behavior.
Menu commands unexpectedly not available.
Missing or blacked-out icons in the Toolbox.
Unusual colors for interface items.

You can reset the preferences file manually:

Start Photoshop while holding down Ctrl+Alt+Shift (Windows)
or Command+Option+Shift (Mac OS X).

Then, click Yes to the message, "Delete the Adobe Photoshop Settings file?"

Here's a detailed video by Deke McClelland