Toon Boom too slow, in art layer

I’ve been through lots of the posts here, and I have not found a solution.

I have Toon Boom Harmony 16, for animating. When i switch to the color layer, it slows down horribly. MORE specifically, when I choose more recent frames. So if i try to load frame 1, it loads fine, frame 8 is slow, frame 15 is veery slow, frame 28 the program crashes. I have messed with lots of preferences. Bitmaping, vector layers, autorendering, light layers and none of these worked. I used a Registry cleaning tool, but it did nothing. I started a new file, copy and pasted manually every layer,(with a lower resolution), at first it worked fine, later it started to crash just like the original file. I also tried File > remove unused files, but it did nothing. It takes like 30 minutes just to load frame 28, and a brush stroke will crash it almost every time.

This happened on 2 different computers. Both are overqualified for the job. In fact I bought a new PC JUST for this program, and made sure I had enough juice. The computer never seems to struggle, its brand new, windows 10, spectre.

This is a file specific issue. Other files work fine. Please… help. Its something within the file, I just can’t figure it out.

my specs just in case:
Intel Core i7
64-bit os,
16 RAM, 15.7 is usable

It might be worth mentioning I’m using an external memory to save all my fies, 1 TB, seagate.

Project resolution is at 720p.
default canvas size and pixel density for bitmap drawings: w2560 h1440

its 57.8 mb, 359 files idk if thats normal or i’m doing something wrong please help.

I’m having the same issue. I was hoping someone would’ve replied.