jhamlin I'm not 100% sure about the "icons on the left", but I'm assuming you are referring to icon previews of embroidery designs in the Finder (screenshot). Please elaborate if I'm mistaken…
There is a Finder option controlling these icons: Please use the menu item "View" - "Show View Options" and enable "Show icon preview" in your embroidery folders. With this option checked your Mac needs some time to generate the corresponding thumbnails after StitchBuddy was installed - and potentially again after macOS updates. You can speed up this process to some extent by entering the following command in the Terminal app (to be found in the Utilities folder) and rebooting your Mac:
qlmanage -r
But it still takes time…
In case the embroidery icons for your PES files aren't shown permanently, I can offer some enhanced debugging instructions, maybe another app is claiming the same file name extension for its QuickLook plugin. But let's cross this bridge when we get there.
Edit: I'm just realizing that maybe your Finder's left sidebar is hidden, which is showing favorite storage locations, drives and tags. If that's your problem you can toggle it using the "View" - "Show Sidebar" option in the Finder…