This is a known issue and has been caused by the server running the SQL Database for the application having run out of space and so being unable to modify the data.
Contact your IT department and have them check the status of the Server running the SQL Database.
Error - 'Failed to add lock for .....' opening Take Off Project
Error received when trying to work in a Project in Take Off. As soon as you double click the porject required the following error is received: Failed to add lock for DXAPI_TYPE_PROJECT: (project guid) (DXAPI_LOCK_OPEN) Failed to update Project (error 3)
Written by Magda Antonie