I can open smaller tifs no problem, but these tifs at 100+MB cannot be opened in Paint.NET. I don't think it's memory issue, because other software can open with no problems (IrfanView, XNViewPortable). Is this a software limitation?
"There was an unspecified error while opening the file."
I'm using Paint.NET v3.5.5 (Final Release build 3.55.3767.28608) on XP SP3.
I think Joel Coehoorn's answer is on the right track. I converted the image to black/white resulting in a file size of just under 5MB. Then attempted to open and received the error again.
Using the original, I tried all sorts of things and eventually figured out that if I reduced the pixels from 6000x6000 to 5000x5000, I could open the image in Paint.NET (even 24bit color).