[pismo50]

After a crash, the server presents a blue screen with the mouse pointer and nothing else ! (just before the normal desktop with login window). From a remote computer, the file service is visible as normal. The crash happened after the launch of the Retrospect uninstall module.
During the start-up process, the splash screen comes and the bar graph shows the progression, but the names of the loaded modules are not visible as with a normal starting server. At the end, the splash screen disappears and the screen stays blue.
Has anybody seen something similar ? It would be good if we could awoid reinstalling the complete system software.
The server is a Dual 800Mhz with OSX 10.1.3 server software.

[SV Mac Maven]

Yes, I have seen this twice. You might have damaged the "Catalog Header" and/or the "Volume Header Block". Try these in this order; if the first doesn't fix it, try the second.
1) Start up with the OS X server installer CD. After start-up, run Disk Utility (find under the File menu) from the CD.

If that doesn't find anything try--
2) Start up with a copy of "Disk Warrior" and run.

If that doesn't find anything try--
3.) Start up with a copy of ,"Norton System Works v 2.0"

One of these always has fixed the problem and returned my machine to normalcy and my peace of mind. I hope you have one of these software tools; I find them indispensible.