UPDATE FROM MABULA
I have had a very rough 2 months unfortunately health wise. I was struck 3x in a row with bacterial infections. The second infection occurred  after a routine hospital checkup and I became very sick. I had to rest and take a lot of antibiotics. Once I was recovering and restarting work 1 month ago, I again became sick. The infection was not yet gone, so even more antibiotics and rest was needed. Needless to say, it took a lot of my energy and I needed a lot of rest.
Finally, the infection is really gone and my energy is coming back step-by-step now and I have started work again. I am terribly sorry to have kept you waiting for support. I will address all outstanding questions and e-mails step-by step and will be on the forum daily from today.
APP 2.0.0-beta47 will come soon as well, a lot of work was already completed before I became very ill, so the release is also nearly ready for you. Beta47 will be much faster actually. Many workflows will be more than 2x faster, mosaics can even be 10x faster than before because registration really received a major boost... all compared to beta46. Â Before I release it, I will make sure that everything is working properly and then I will release it.
If I remove the flats and darks, this error message does not come. BIAS work alone.
This is with 1.077 right? And the exact same frames didn't cause an issue with 1.076 or 1.075?
Yes, that happened with the update to 1.077
I have now installed 1.075 again. Now I have the same error message here.
I'm testing other data, here is the same error message.
Obviously this error message comes from the Darks. Now I only used 30 of the 50 from the middle. And now it works 🙂
I uploaded the 50 darks here. Maybe this will help you find the mistake.
Dropbox File (Private or Invalid)
Ah great, yes it sometimes happens when calibration data has some issue. Might be worth for you to check the difference between the darks that didn't work and those that did, just to prevent it in the future. Thanks for uploading, can you pinpoint which frames caused the issue?
I looked through the darks one by one and saw no anomalies.
That error is indicative of a problem where you are calibrating data that incomaptible like monochrome data with Bayer CFA or 3-channel (RGB) Master frames or vice versa... check your data, if it's Bayer CFA data, have you enabled Force CFA in 0) RAW/FITS? Are all masters created as CFA masters?
Can you share frames of all types? Some lights, darks, flats, bias? I will make sure that it is solved.
Mabula