How to Fix 'Company File in Use' in QuickBooks Multi-User Mode The "Company File in Use" error in QuickBooks Multi-User Mode appears when several users try to access the company file at once or when the file is locked as a result of incorrect closure or network problems. The corporate file remaining open on another user's computer is the most common reason for this issue. If you have a multi-user setup, be sure that no one else is currently reading the file. Make that no other users in the network or organization are using the file. For More : https://a2autocare.com/article/locked-out-of-my-data-file-quickbooks-file-in-use-solved/