Windows Defender Issue


I'm getting the attached message when opening linqpad, and it is almost certainly related to Windows Defender and real time threat protection. (https://us.v-cdn.net/5019392/uploads/editor/bb/o68ui3i7o5y8.jpg "")

I am definitely seeing timeouts and odd behavior on occasion. Do you have any whitelisting or other strategies that can help mitigate anti-virus software getting in the way?



  • There are a couple of things you can try. The first is to disable cloud-delivered protection under "Virus & threat protection settings". There appears to be a bug in Windows Defender's cloud-delivered protection that sometimes causes it to go overboard in choosing which files to submit for online analysis. This is an intermittent bug that comes and goes, sometimes causing a problem for several days/weeks before disappearing. It can also affect build and run times in Visual Studio.

    The second is to whitelist LINQPad. You will need to whitelist the following executables:


    You should also check that there is no other antimalware software on the machine.

    Let me know how you get on.

  • Thanks for the information Joe. The cloud-delivered protection issue sounds quite similar to what I'm experiencing. Unfortunately I don't have rights to disable that feature on this machine. I have been able to get those executables whitelisted.

  • Love linqpad by the way, use it constantly

  • I had a similar issue.

    I whitelisted the suggested files to no effect.

    Only when I turned off cloud protection did the numbers drop from 300-400ms to 20-30.

  • With Windows Defender, you'll get better luck whitelisting the processes rather than the files. Under Virus and Threat Settings, Exclusions, click Add Exclusion > Process, and whitelist the following:

    For LINQPad 8:

    • LINQPad8.exe
    • LINQPad8-x64.exe (or -x86 or -arm64)

    For LINQPad 7:

    • LINQPad7.exe
    • LINQPad7-x64.exe
    • LINQPad7.Query.exe

    For LINQPad 5:

    • LINQPad.exe
    • LINQPad.UserQuery.exe
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