Hi,
I was importing a large number of files, and DTPro kept crashing mid import. So, needless to say, that database creates an in use error when i open it. But, even if i create a new database, when i first create it, i get an in use error and nothing works.
I suggest that you locate the most recent DT Pro crash log and attach it to a message to Support, including a brief description of what you were doing.
The ‘in use’ message will be triggered by an event in which the database isn’t properly closed.
Do you have at least 15% free hard disk space remaining? Check your remaining disk space using Activity Monitor.app (Applications > Utilities). Apple’s engineers highly recommend keeping a reserve of free disk space for temporary files and for Virtual Memory swap files.