server Error : this database cannot be read due to an invalid on disk structure

Resolving the problem

This issue can occur if the user has "Always keep a copy" selected for the "Save mail that you sent" option under File > Preferences > User Preferences > Mail. If changing this setting to not keep a copy allows the user to successfully send the message, this would indicate a problem with the Sent folder being corrupt. Running fixup, compact and updall on the mail database should resolve the problem in this case. In one case, running these utilities did not resolve the issue and resulted in additional errors such as "Database is corrupt -- cannot allocate space." Further, when this database was opened in a browser, the error "HTTP Web Server: Lotus Notes Exception - Special database object cannot be located" displayed. Finally, an attempt to recompile all of the LotusScript code in the database resulted in 'Invalid syntax' errors.