if that doesnt help:
Up to Illustrator 10, almost all the preference settings were included in the AIPrefs/Adobe Illustrator Prefs file, and almost all issues with corrupted settings could be solved by deleting or moving it; in some rare cases, moving or deleting the folder holding the settings was required.
From Illustrator CS on, the preference settings have been spread over a number of files/subfolders so in many cases deleting the AIPrefs/Adobe Illustrator Prefs file is not enough: the easy solution is to move the whole folder rather than trying to figure out which file(s) may be corrupted; just deleting the folder without moving it first has proved fruitless in some cases.
Therefore, the cure all consists of the following steps:
1. Close Illustrator.
2. Make a search (including hidden files and folders in Windows) and including subfolders for the folder holding the preference files; the name of the folder depends on the Illustrator version, and the position of the folder depends on the OS version. There is one folder for each version and for each user so it is important to find the relevant one.
Up to version 10, the name of the folder is Adobe Illustrator [X],
From version CS on, the name of the folder is Adobe Illustrator [X] Settings.
[X] is the version number; up to 10, it is just a number, and above that the Creative Suite version number, CS, CS2, CS3, CS4, and so on, is used (the corresponding standalone versions still have simple numbers, CS is called 11, CS2 is called 12, CS3 is called 13, and CS4 is called 14, but the version numbers with CS are used in the folder name).
3. Either:
a) Create a subfolder and move all the contents into it; or
b) Move the whole folder to a place where you can find it again, such as the Desktop.
With both you may recover the contents of the folder by moving it back if the issue is not solved and get your preference settings back.
a) requires creation of the subfolder, but it makes recovery easier, especially if you create a shortcut to the preference settings folder, and you can skip the search if/when corruption occurs again.
You may delete the folder/contents subsequently.
4. If you have Windows Vista, restart Windows. If not, continue to 5 without delay.
5. Restart Illustrator, and see whether the issue is solved.
If the issue is solved, and you wish to keep as many of your preference settings as possible, you may move the folder back and repeat 3) - 5) for groups/individual files/subfolders until you have found the corrupted one(s). You may also start by only moving the AIPrefs/Adobe Illustrator Prefs file.
