Why are images are missing from my Stacks page?
In the past when we've seen file corruption issues (or missing images) when the user is running a utility or “cleaner” that has noticed a large cache directory and decided to “clean” it of images. Utilities like CleanMyMac, MacKeeper, and MacCleaner.
If these "Cleaner" utilities are run while RapidWeaver and Stacks are open, they can be aggressive when they see a very large cache of images. Running these when RapidWeaver is closed is fine, of course – but removing cached images while RapidWeaver is open can affect the integrity of the file
Never use CleanMyMac, MacKeeper, and MacCleaner while RapidWeaver is open.