www.makemkv.com

Been using MakeMKV 1.9.5 for a couple months on Windows 7 without issue.

Went to use it yesterday and it crashed as soon as I started it. It has done nothing but crash since then.
I rebooted and it still crashed. Disabled the antivirus, still crashed. Uninstalled and reinstalled, still crashes. Downloaded fresh copy from makemkv.com, uninstalled and reinstalled. Still crashing.

Can anyone help?

Problem Event Name: APPCRASH
Application Name: makemkvcon64.exe
Application Version: 0.0.0.0
Application Timestamp: 55b55755
Fault Module Name: ntdll.dll
Fault Module Version: 6.1.7601.18798
Fault Module Timestamp: 5507b864
Exception Code: c0000005
Exception Offset: 000000000004e128
OS Version: 6.1.7601.2.1.0.768.3
Locale ID: 1033
Additional Information 1: 3a9b
Additional Information 2: 3a9bd2f3680d96275b17b25fa5124f79
Additional Information 3: 7249
Additional Information 4: 724993b4844351df2dca2bf679502e82

I'm having exactly the same problem - and have posted in a different thread (you can find it pretty easily). Someone has suggested there that it might relate to certain Windows updates.

I've installed it on three Windows 7 machines - all with the same problem. They all, also, run Bit Defender. Following advice elsewhere (in this forum) I've added some additional firewall rules - they have not helped. I'm tempted to remove Bit Defender as I suspect it interferes with a lot of stuff.

My crash details are somewhat similar to yours (the precise fault module version is slightly different):-

Problem Event Name: APPCRASH
Application Name: makemkvcon64.exe
Application Version: 0.0.0.0
Application Timestamp: 55b55755
Fault Module Name: ntdll.dll
Fault Module Version: 6.1.7601.18933
Fault Module Timestamp: 55a6a196
Exception Code: c0000005
Exception Offset: 000000000004df08
OS Version: 6.1.7601.2.1.0.768.3
Locale ID: 2057
Additional Information 1: 3a9b
Additional Information 2: 3a9bd2f3680d96275b17b25fa5124f79
Additional Information 3: 7249
Additional Information 4: 724993b4844351df2dca2bf679502e82

The problem is BitDefender Free. For some reason it kills MakeMKV.

Uninstall BitDefender Free, problem went away.

Now using Avira. Shame, I liked BitDefender's minimalist approach.

At least two antivirus products have started to give generic "could be malicious so we're stopping it" problems with MakeMKV. Searching for the information on what the warning meant pointed to activity like contacting outside systems. When MakeMKV checks for new versions or SVQ files, it contacts this website....

IP Results
Source: makemkv.com
IP: 5.178.87.118
Location: St.-Petersburg, Russia

That alone might be enough to cause this.