QuickBooks Errors 6190 and 816 often occur when accessing a company file in a multi-user environment. These errors typically indicate a mismatch between the transaction log file (.tlg) and the company file (.qbw), preventing users from opening the file. Common causes include file corruption, network issues, or another user accessing the file in single-user mode. Resolving these errors involves using the QuickBooks File Doctor Tool, verifying multi-user settings, and ensuring proper file hosting. For seamless troubleshooting, consult an expert. Contact QB Data Service at +1-888-538-1314 for tailored support and to keep your accounting processes running smoothly.