It's going to be difficult to troubleshoot the reasons, so here is another way to save time.
Edit > Presets > Export/Import Presets > Export Tab
Select and Move your workspaces to the right column. Click on Export.
Save to Windows Desktop. It will be named "Exported Presets"
Move the Exported Presets folder to the Destination Mac's Desktop. Open Photoshop
Edit > Presets > Export/Import Presets > Import Tab
Select Import folder. (Select Desktop, click on Open) Move the Workspaces to the right column, then click on Import.
Your imported workspaces should be in the Workspace dropdown menu