AddIn modifications not saving on different PC

I am befuddled. I loaded an Addin I created on my work PC to my home PC to modify it. I made some minor changes, saved it periodically while I was working on the code (nothing happened to indicate that those were not saving). Then I closed the vba editor - closed Excel - no message popped up about asking to Save. Then I went back to it later and poof none of my modifications were saved! I verified that the Addin was in my addins folder and that was the one I had loaded to my Excel. The date on the original addin was the original pre-modification date. What happened?? And what settings would I need to change on the home PC to allow me to work on it?

Both PCs are running Windows 10 and I am using Excel 2010 for this Addin.

Thanks,
patb