So i noticed a bug in Winbox version mentioned in subject of this thread. When i open up Winbox and go to IP->DNS then click on "Cache". When i choose filters, if i select "Data" filter winbox will immediately crash. It will exit the app. Regardless of which router I'm connecting to (i have two mikrotiks in my home, both different model).
If i choose any other filter it will work fine.

I'm using this on Windows 10

1. Backup your Addresses from Winbox
2. Go to %APPDATA%\Mikrotik\Winbox and delete everything.
3. Remove the contents of the folder where you have your winbox.exe and download the latest from mikrotik.com
3. Restore your Addresses
4. Test

Tried to replicate your issue and I could not get Winbox to crash.

later edit:
It seems I was using Winbox 3.17 instead of 3.20
Tried with 3.20 and indeed, it crashed as the OP stated.

I am able to duplicate the issue with Winbox x64.

Edit: I'm using Windows 7.

I am also facing this issue.
I am using Winbox v3.20 on Windows 10 to manage a CCR1009 running RouterOS v6.45.8.

This is resolved for me in Winbox 3.21 x64 on Win 7.

what he said ^