Overview
Windows 10 ships with its own built-in antivirus software, Windows Defender. This is a good feature to have in any operating system. However, if another antivirus software is installed on the computer, Windows Defender should be disabled automatically. This is not always the case
We have seen several incidents where Windows Defender continues to scan opened files and ongoing processes even though there is already another antivirus software doing the same. This has led to numerous different error situations, like:
- Multiple "File downloaded" events M-Files Admin event log
- Excel program opening when previewing an Excel document in M-Files (and the preview doesn't work if Excel is not open)
- "Violation of PRIMARY KEY constraint 'PK_DATAFILEVERSION_BYTES'. Cannot insert duplicate key in object 'dbo.DATAFILEVERSION_BYTES'. The duplicate key value is (9810, 1, 0, 1). (ERROR: 2627, SQLSTATE: 23000)" error in M-Files client computer event log
- General slowness of M-Files usage
Solution
As M-Files shows up on the client computer as a regular drive, the antivirus software also tries to scan it for harmful content. However, M-Files works differently from a normal drive and antivirus software's real-time scans can cause a multitude of problems. That is why we recommend excluding M-Files from real-time antivirus scans, regardless of the antivirus software used: https://www.m-files.com/user-guide/latest/eng/m-files_and_virus_scanning.html
In some cases, this is not enough, and Windows Defender still interferes with using M-Files. In those cases, it is worth trying to disable Windows Defender. More background information and instructions on how to disable Windows Defender can be found e.g. here: https://www.windowscentral.com/how-keep-windows-defender-disabled-after-installing-third-party-antivirus-windows-10 (this link is not maintained by M-Files)
