Again: "files are supported but something went wrong"

[soren2]

Hej
The majority of my ppt and pptx files cant be previewed or opened at my computer after downloading. Another example is one text-file that in preview only shows "garbage". 
I have tested 2 different computers with Edge and Chrome and on my Iphone.
Someone with any idea what this can be. It is probably >5 years since I put  the files on Dropbox.

[Sanchez]

Hey, @soren2, thanks for getting in touch. 

What happens when you try to open them on your computer, with MS Office? Do you get any errors or other messages? 

If these files are not working online, or after downloading them, it would suggest that they are corrupt. As Dropbox doesn’t alter your files in any way, this would mean that the original uploads from >5 years ago were corrupt (not fully functional; damaged in some way). In this case, there isn’t anything that we can do to help, unfortunately. 

Get back to me when you can! 

[soren2]

I get "PowerPoint can't open this type of file."
It is strange that it is all ppt but not photos or xls-files.

[soren2 · Accepted solution]

I have now archived the files, outside dropbox. Probably is time my best friend, in other words the probability that I will need to use the files in the future is low.
Thanks for the help and I consider now this question as closed, from my point of view.