QuickBooks is unable to open the company file it may have been opened by another user in Single User mode. Learn how to fix the QuickBooks error -6073, -99001 QuickBooks is unable to open this company file issue https://www.askforaccounting.com/quickbooks-error-6073-99001/ #QuickBooks607399001 #QuickBooksError #SingleUserMode #CompanyFile #QuickBooksToolsHub #QuickBooksDesktop #AskForAccounting