Same here. This whole day I edited MTS (AVCHD) sources with VP17 build 353 without any trouble. Windows 10 here.

Thanks for the quick help. I am at work now will give it another try tomorrow. I've never had this type of problem before

Camera AVCHD and HDV MPEG -2 are commonly wrapped .mts.

Post-acquisition, they are often .m2ts, but that can vary a lot.

(@set: MTS is an AVCHD format right?) Yes, files came from a Panasonic camera.)

I just tried these files in SonyVegas version 13, MagixVegas version 15, and Magix Vegas 16. ALL loaded and worked as expected. Again tried MagixVegas 17 - 353 and an immediate crash once I click on any of the files.  I'm at a complete loss here. Not a computer guru, but I suppose I am to uninstall version 17/353 before I try to download version 17/321?

Windows 10 is in the minimum requirements, as such, I'd expect to see more and more stuff stop working in 7 as time moves on.

I realize the minimum is Win10 - NOW. However, I bought version 16 (which is fine with Win7) that also included an upgrade to version 17 when it was released. I never read where the future version 17 was going to be crippled in Win7. In fact, at the time of this offer, there was no information regarding requirements for version 17 published that I know of. I am not trying to be critical about these changes as I realize it was inevitable but had I known this in advance, I probably would not have taken advantage of the offer at that time. Not trying to stir up hate and discontent, just trying to explain how I got into this situation.

I am also having trouble editing AVCHD files. MTS, since I upgraded to the new version of Vegas Pro 17 build 353. But earlier in the buil 321 version, I edited all the files beautifully. I did not make any system changes (W7 64 bit). Please does anyone have a solution?

Thank you for that confirmation!  When someone reports an issue it is comforting to know that one is not crazy. To follow up on this issue, I followed "set's" link above. I deleted my Build 383, and reinstalled Build 284 and all is well again. All files are behaving and are recognized again.

I would not see that as a Long-term solution, since you go back to older versions and you will not be able to install upcoming updates too.

The solution should be to upgrade to Windows 10, since that is what is required for Vegas Pro 17.

@Wolfgang S. - I acknowledge that I will have to move to Win10, but Vegas is not the only software I work with on a regular basis. I have a multitude of business software programs that would have to be updated/modified if I moved to Win10. This would entail redesigning forms, invoices etc. This alone would take several weeks or even a couple of months to accomplish. I even keep one computer loaded with Win98XP for 2 programs that are very efficient but were not updated to run in Win7. Vegas is only a hobby for me. According to my wife, it is more of an obsession. Anyway I appreciate the patience that some have shown me in dealing with the few issues I have had.

So understandable that is - unfortunately it is only you will suffer from that in the Long run.

I had a similar Situation for a dia scanner Software running only under WinXP too. So I know that quite well. But when the power supply crashed in that machine, I upgraded the Software since that was necessary anyway.

@Wolfgang S. - I acknowledge that I will have to move to Win10, but Vegas is not the only software I work with on a regular basis. I have a multitude of business software programs that would have to be updated/modified if I moved to Win10. This would entail redesigning forms, invoices etc. This alone would take several weeks or even a couple of months to accomplish. I even keep one computer loaded with Win98XP for 2 programs that are very efficient but were not updated to run in Win7. Vegas is only a hobby for me. According to my wife, it is more of an obsession. Anyway I appreciate the patience that some have shown me in dealing with the few issues I have had.

Just on the off chance that you don't know Windows compatibility mode may help, e.g an older program would think it is running under an older os. Of course won't work for all programs. https://www.computerhope.com/issues/ch001894.htm