I see this notification when I use bakemaster to bake Udim texture (4K), don’t know how to solve it 
Not much info to go on…I don’t know Bakemaster but the error seems to be saying there isn’t a way to save " as yet a non-existent bake, it is still in memory" internally in the Blend…
Did you save out the Baked images to files before trying to save the Packed Blend?
Thanks for reply， this addon will automatically save and pack the baked image to file when finish baking
And I tried several times to bake UDIM texture, somehow it succeed a few times, but most time the error notification occurred. this is my setting in bakemaster
UDIM tiles cannot be saved into Blender (Blender itself doesn’t support it). The option for you here is to save externally to the disk:” by unchecking ‘Internal’ and choosing ‘Output filepath’ in the ‘Bake Output’ panel:
