I had a client that kept having Amicus 5.5 crash when a particular user would add a contact. No one else was having this problem. The consultant that they were using told them to unlock all data and try and rebuild their database. This did not work and the client became frustrated. They decided to call me and made it very clear that they had tried unlocking all data and rebuilding their database multiple times. When only one user in your firm is getting validation errors when they create a contact, a calender event, or a file, it probably means there are no default team members assigned to that module in Amicus. To check this, go to Preferences --> The Module (Contact, Calender, File) --> New Entries. Make sure that there is one or multiple team members assigned to the new entry section.