Should specify it doesn't crash the game, but locks it up when starting the game about 80% of the time.

Closing this since we can't reproduce it, and you have not provided us a log file or any other information. After testing in dev environments and in production for both Fabric and Forge we never ran into any freezes, however if you run into the issue in the future, please reopen this issue and attach a log file, as well as a video if possible.

For future reference, please fill out the issue template when making a report rather than simply just describing the problem - the template tells you everything you need to include for us to be able to try and solve the issue.

we can't do anything without a log file.

Any information at all helps. Minecraft version, C+ version, which loader you're using/loader version, a video, other mods you're using, etc. Just saying it locks up on launch doesn't help us much in figuring it out because we don't know what we're looking at/for. Please add more information sometime soon (within the next few days) or this issue will be closed.

and a log has all of that info in it.