Question

Studio One 6.5 freezes while loading and playing a song.
In the picture, while loading the VU meter, but it also happened while loading Waves Studio Rack, which I could only solve by directly modifying the song file (I removed the preset).
It often freezes during playback, and even then it can only be stopped from the task manager. Unfortunately, I don't get any information about the cause of the problem.
I reinstalled the operating system (Windows 11) due to motherboard and CPU replacement. I re-registered Studio One and plugins.

Unfortunately, I can't use Studio One this way.

UPDATE: After Studio One 6.6 update:

Answer 1

I use both of the plugins and it works fine for me. 
Try uninstalling the waves studio rack and vu meter.
Change your block size to 1024 or high and if that still fails to give you smooth audio.

You might have something running on your system that making your audio processing slow.

Install latencymon, run and see what driver might cause this. 
Resplendence Software - LatencyMon: suitability checker for real-time audio and other tasks

• Best you update your drivers
• Set you power plan to performance
• disable cpu throttling

I had this issues way back and noticed it was onedrive that slowed my system at a time which made me to pause it for 8 hours or disconnect from the internet.
I also used a tool called atlas os which will modify your windows system, removing bloat and not need services, making windows lite that will your final option.
AtlasOS - An optimized modification of Windows, designed for gamers.

 
Please note this is my opinion and it works for me.
I hope this works for you.

Answer 2

Thank you for your reply.

There are two problems, one is that Studio One freezes when loading, and the other is that it freezes during playback.

The loading problem first appeared in another project. It always stopped there when loading the Studio Rack. I did a clean reinstall of the Waves plugins with help of Waves support, but it didn't fix the problem. I finally managed to solve it by removing the used Studio Rack preset from the song file. After that, it loaded successfully and I re-selected the used preset in Studio Rack. After that, I didn't experience the freeze while loading.
In another project, the Presonus VU meter stops loading. After installing the Studio One 6.6 update, it also stops on the Studio Rack.

I don't have that much information about the cause of the complete freeze during playback (but not experienced since the 6.6 update). The sound does not stutter, but Studio One freezes and stop playing.

The size of the buffer is 1024, and during playback the CPU performance meter shows ~48%.

Before reinstalling, I used a performance-centric setup with the previous motherboard and CPU, but the current configuration is much more powerful. And I tried it before, but it didn't help.

By the way, there is another issue, but it is not specific to Studio One. But I can no longer rule out the possibility that the freezing of Studio One and the problem written below are not caused by the same thing.
I use KRK Rokit 5 studio monitors, and after replacing the motherboard, the speakers automatically turn on at random times (volume is 0 on sound card and no input device is connected). Sometimes, when they are already on, but I'm not playing a sound, I hear a pretty loud pop. Maybe this crack used to turn them on, but I can't hear it then. I tried plugging the sound card (SSL 2+) into another USB socket, but it didn't help. There was no such problem with the previous configuration.