Several months after every QuickBooks Pro and Enterprise annual upgrade my clients run into an issue where they cannot connect to the QuickBooks database with messages indicating, the application cannot access the database, and H2020 Error, or QuickBooks is unable to open this company file due to the file being open on another computer in single user mode. Most recently, as per the image below:
I have found over the years the solution is to open the services management console ( services.msc ) on the server or computer hosting the data, scroll down to locate the QuickBooks service named “QuickBooksDBxx”, where xx = a number relating to the current version. If you have installed multiple versions over the years there will be one for each year. You want the one with the highest number. (note in the images below the changes have already been made)
Double click on the service to open the properties for that service and click on the “Log On” tab. The radio button “This Account” will be checked, a QBDataServixeUserxx” name will be shown, and a hidden password entered. Change to “Local System account”, click apply and close, then right click on the service and choose start. (NOTE: if you change this setting to service account and want to change back for some reason you will likely need to re-install QuickBooks)
You now need to run the “QuickBooks Database Server Manager” app from the programs menu, in the QuickBooks folder. Under the Scan Folders tab make sure the folder that contains your data is shown If not browse to it and select, then click the “Start Scan” button. It should show “successful” when done and you can choose close. Assuming you have the same issue, running this wizard before making the change above will result in “failure”.