Open up the file and then right click on them in the assembly feature tree and select set to resolved. SW will read the file and it should fix.
Other way would be to let SW prompt you for the missing file. To do this go to Tools > Options > System Options > Messages/Errors/Warnings and make sure there is no message about missing file or unable to locate. If yes then tick that one and click OK. then open up your assembly and SW should ask you for the missing files.
The next way would be to click on assembly in the open dialog box but don't open it. Now click on references in the same box and then fix the location for the files as required. Finally open the assembly and check.
Thanks Deepak. I knew there was a way or five to handle the problem. The goof-ball fix I found was to do a “replace components” on one of the un-suppressible parts… it would not allow me to replace the component with another of the same name but after hitting cancel the location was resolved and everything unsuppressed. Why did that work? Beats me. My biggest problem was that I don’t remember this ever being a problem before.