A duplicate value cannot be inserted into a unique index. [ Table name = ProjectInfo,Constraint name = IX_FMProject ]
This error usually occurs when checking projects in or out of SI5.
Warning: Before attempting this solution make sure that all projects are checked into the server. Deleting the LocalFileManager.sdf handles the file management for your local projects and will remove them from your local project list once file is deleted.
1. Navigate to:
XP: C:\Documents and settings\username\Application Data\D-tools\SI5
Win7/Vista: C:\Users\username\AppData\Roaming\D-tools\SI5
2. Rename the LocalFileManger.sdf to something like "OLDLocalFileManager,sdf"
3. Restart SI5