Mac freezes on login

Question

i have 7 different "desktops"  the first logon is ok...lately...if i try another...it will freeze....any thoughts or suggestions..
first time writing

Answer 1

The next time you have the problem, note the exact times when it starts and ends: hour, minute, second.
If you have more than one user account, these instructions must be carried out as an administrator.
Launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ If you’re running OS X 10.7 or later, open LaunchPad. Click Utilities, then Console in the page that opens.
Make sure the title of the Console window is All Messages. If it isn't, select All Messages from the SYSTEM LOG QUERIES menu on the left.
Scroll back in the log to the time you noted above. Post any messages timestamped during that interval – the text, please, not a screenshot.
Important: Some private information, such as your name, may appear in the log. Edit it out by search-and-replace in a text editor before posting.