If that didn't work then rebuild your iPhoto Library with this third party application, iPhoto Library Manager (just try the trial version) -----> http://www.fatcatsoftware.com/iplm/To rebuild with iPhoto Library Manager, open iPhoto Library Manager, click on File menu and select Rebuild.
Please let me know if that didn't work, so we can continue troubleshooting.
Is option alt on the German keyboard?
The first solution did not work. I am now waiting for Library Manager to rebuild. Ted
The rebuild is complete and I went through all 8000 pics twice. I found no more exclamation marks, but I suspect the damaged pictures were deleted. I had three or four which I knew were damaged and I cannot find them now. Ted