--- a/toolkit/mozapps/extensions/internal/XPIProviderUtils.js
+++ b/toolkit/mozapps/extensions/internal/XPIProviderUtils.js
@@ -497,16 +497,19 @@ this.XPIDatabase = {
         // force the DB to save so that the DB_SCHEMA value in the JSON file and
         // the preference are updated.
       }
       // If we got here, we probably have good data
       // Make AddonInternal instances from the loaded data and save them
       let addonDB = new Map();
       for (let loadedAddon of inputAddons.addons) {
         try {
+          if (!loadedAddon.path) {
+            loadedAddon.path = descriptorToPath(loadedAddon.descriptor);
+          }
           loadedAddon._sourceBundle = new nsIFile(loadedAddon.path);
         } catch (e) {
           // We can fail here when the path is invalid, usually from the
           // wrong OS
           logger.warn("Could not find source bundle for add-on " + loadedAddon.id, e);
         }
 
         let newAddon = new DBAddonInternal(loadedAddon);