I have an exr exported from karma, if I bring the file in via COPS it reads all the channels properly but if I bring it into fusion, gimp, affinity photo it doesn't import the channels. However it did import using the exr-IO plugin for Photoshop and then I could export it into a new exr which did read properly in the rest of the programs, however I don't have a license anymore. Anyone know why this is and how to fix it? I was assuming it was some sort of issue with exr versions but I didn't know how to check that. Is there a free software to view multilayer exr and export them that might solve this problem?

If indeed multipart exrs are the problem, you may check out this posting on how to revert to "the old" regular ones:

https://www.sidefx.com/forum/topic/81532/?page=1#post-351236 [www.sidefx.com]

That did it, thankyou!