If you are the only person working on the file, this error means that NVivo or the computer was shut down before the SQL log file (.ldf) could be closed out by the software. Please use File Explorer to navigate to your .nvp file and locate the corresponding .ldf file. Once you find it, delete it. Once it's deleted, you should be able to open the .nvp file in NVivo. If this fails, check the Task Manager utility for SQL or any Nvivo related processes still running on the device with NVivo closed. Stop the tasks, restart NVivo and try opening the file again.