Windows XP: Click the Start menu > Control Panel > Add/Remove Programs > SketchUp #.

Windows Vista/Windows 7: Click the Start (Windows logo) menu > Control Panel > Programs > Programs and Features > SketchUp #.

To uninstall SketchUp, select Remove (Uninstall on Vista or Windows 7). When asked if you'd like to remove SketchUp, click Yes.

If you are having problems with SketchUp, you can try the Change option, which begins the process of reinstalling the program features that were installed during the last installation. This can fix any application files that were corrupted (this doesn't affect or fix your SketchUp drawing files, the SKP files). If that doesn't work, try uninstalling and reinstalling SketchUp.

1. Quit SketchUp. (If you have more than one instance of SketchUp open, make sure you quit all instances of SketchUp.)
   
2. Open a Finder window.
   
3. (SketchUp 8 and older) Delete the SketchUp folder from the main library:
   
   1. In the left pane of the Finder window, click Macintosh HD.
      
   2. In the right pane, click Library, and then Application Support.
      
   3. In the Application Support folder, find the Google SketchUp # folder, and then drag it to the trash.
      
      For SketchUp 2013 the folder will simply be "SketchUp 2013".
      
4. Delete the SketchUp folder from your user library:
   
   1. In the left pane of the Finder window, click your user name, then click Library* in the right pane.
      
      1. *If you're using Mac OS X 10.7 or newer, hold down the Option (Alt) button on your keyboard, click Go in the menubar, then select the Library option in the drop-down list. Here's an example video.
         
   2. Open the Application Support folder.
      
   3. In the Application Support folder, find the SketchUp # folder, and then drag it to the trash.
      
5. Delete the SketchUp application:
   
   1. In the left pane of the Finder window, click Applications.
      
   2. In the right pane, find SketchUp # folder, and then drag it to the trash.
      
6. Delete the plist file:
   
   1. In the left pane of the Finder window, click your user name.
      
   2. In the right pane, click Library*, and then Preferences.
      
      1. *If you're using Mac OS X 10.7 or newer, hold down the Option (Alt) button on your keyboard, click Go in the menubar, then select the Library option in the drop-down list. Here's an example video.
         
   3. In the Preferences folder, drag any of the following files, if present, to the trash:
      
      • com.atlast.sketchup.plist
        
      • com.google.sketchuppro.plist
        
      • com.google.sketchupfree.plist
        
      • com.google.sketchuppro7.plist
        
      • com.google.sketchupfree7.plist
        
      • com.google.sketchuppro8.plist
        
      • com.google.sketchupfree8.plist
        
      • com.google.LayOut.plist
        
      • com.google.style_builder.plist
        
      • com.sketchup.SketchUp.plist
        
      • com.sketchup.LayOut.plist
        
      • com.sketchup.StyleBuilder.plist

7. Empty the trash.