Alt Shift start always required to start premiere

I have a premiere project with ~30GB of mts files.

One I start premiere using Alt Shift the files are loaded and then I have no issue to view them.

However, when I close premiere and start again without Alt Shift pressed, I can't really see the mts files.

I sometime able to hear and in the screen get the "media pending" message and usually after a while even this doesn't work and I can't do play at all.

If I close again and then re-start with Alt Shift it starts o.k. and I can see the mts files with video.

Any ideas?

I thought it maybe related to memory using software or GPU but both has the same issue.