Digital Light & Color

Picture Window Pro 8.0.283
Windows 11.

I just made some editing to a bunch of TIFF files with GIMP 2.10.30 and none of them are recognize as valid files by PWP.
Looking for a solution I have found this on a recent GIMP version changes:

___________________________________________________
TIFF exporting used to lock the TIFF files because of a bug in the Windows thumbnailer (Explorer.exe would acquire a lock on the file and never release it). Since Microsoft doesn’t seem to want to fix this long-standing bug, we decided to switch to another way of creating thumbnails by adding a “reduced-resolution image” as the second page of the TIFF, as proposed in the TIFF specification, instead of adding a subifd thumbnail. This takes care of the lock issue in a nice way, bypassing Explorer‘s bug. Of course, it means that programs that can’t reads tags properly might try opening thumbnails as additional pages, even though it is explicitly annotated as “reduced-resolution image“. If you ever run into this very issue, please report it to developers of such programs. What they need to check is the SubFile type of the pages their software opens (as per TIFF specification).
___________________________________________________

I hope this can help solving the issue.
Jonathan, if you need a sample problematic TIFF, please, ask.
Thank you for your support.

Yes, please email me a sample image (jsachs@dl-c.com).

Here you have:

https://mega.nz/file/GG5j3DBS#z4Dyl0C7J ... Iw2NWux04M

This TIFF file is in 32-bit RGB floating point format (96 bits/pixel) which PWP does not currently support.

If you change the pixel depth of the image from 32 bits to 16 bits in Gimp and re-save you should be OK.

That solved it.
Thank you.
I don't know why GIMP has started saving TIFFs in that format.

I assume Gimp is just saving the images in the format they were created in, and somehow you had it set to create 32-bit floating point images.

Given that the eye and most output devices struggle to produce 256 discernable gray levels, 32-bit floating point is ridiculous overkill for general photography, and 16-bit integer should be fine for almost any usage.

The original image was not a 32 bit one. It's a color chart from Argyll. I just cropped it and saved with another name.
Maybe there is some settings changed on GIMP.