If the warning This file is in use appears when importing invoices from ProFile into QuickBooks, it means access has to be allowed:
- Close both ProFile and QuickBooks.
- Open ProFile.
- Connect to QuickBooks.
- Click OK on the warning message Unable to open QuickBooks.
- Open the file in QuickBooks and allow access to ProFile.
The connection frome ProFile to QuickBooks will now be successful.