Unity 5.4 or 5.5 freezes when I debug my code.

Hi, it’s the first time that I use FMOD in a Unity project. We started the project without FMOD in mind, but the sound designer requested that we use it. The project was working fine. When I added the FMOD plugin integration for Unity and, when I debug the code, Unity crashes. I deleted the FMOD plugin and now I can debug normally.

Unity has logfiles it prints to when it runs. Try checking those to see if you can at least narrow down the last thing to execute before crash.
https://docs.unity3d.com/Manual/LogFiles.html

Unity crashes and does not store any log message.

I might need some more information, what version of the integration are you using?
Have you tried re-importing the integration into the project?
Are you getting any warnings or errors at all in the editor before this happens?

If you would like to link a project that reproduces this error I could take a look.