We run a PC using windows 10 pro 64 bit and inkscape 1.1.  We also run a MAC pro using inkscape 0.94.

If you export a design page with a black object on the page as a png file, the thumbnail initially contains a white background.  If you select the file, the thumbnail and preview background now turns black and remains black.  useless for preview and further it carries over to uploading to a website (like etsy) and show as a totally black image.  this is a new pc on which it worked fine (white background up until this weekend).

If we open the same SVG design file on our MAC Pro and export the page as a png file, the background remains white all the time whether opening / viewing the PNG preview on the MAC, or on the PC,  or uploading to a website.  Always works perfectly and remains so.

This happens with all png files exported on the PC.  Why is this happening on only the PC, only with inkscape generated png files, and always works fine when generated with the MAC?  This also does not occur in any other image creation / modification software on the PC - only from Inkscape.

I have tried all of the remedies I've seen (like deleting the thumbnail images, changing the group policy about saving the thumbnails, etc...).  They all work to correct the thumbnail and preview the first time is show in the directory, however once you select the file, the background goes black again.  I have also tried the inkscape thread suggestion of inserting a white object in the corner of the sheet to "force" a white backgroud.  Sure enough, there is a white object on the black background so that didn't work.

I have also tried this on another PC and had the same issues with every version of inkscape starting at 0.926.

We are dead in the water as we cannot send the png images to customers nor post on a website as they are pure black.