QuickBooks Error 61 typically occurs when accessing company files or during multi-user mode operations. This error often stems from network connectivity issues, damaged company files, or incorrect user permissions. To resolve this issue, start by running QuickBooks File Doctor to scan and repair corrupted files. Ensure all workstations have identical QuickBooks versions installed. Check network settings and verify that QuickBooks Database Server Manager is properly configured on the server. Update QuickBooks to the latest release, as newer versions often contain bug fixes. If the error persists, consider recreating the company file or restoring from a recent backup to ensure data integrity and smooth operations.