SanDisk’s Connect Drive app and screen overlay error on Android Marshmallow

Yesterday I installed and attempted to run the SanDisk’s Connect Drive app so I could access my wireless flash drive from my Android smartphone. However, the app refused to run, trowing an notification explaining that the ‘screen overlay settings‘ must be turned off, or else access permissions could not be set. This problem persisted until, after launching the ‘recent application menu‘ (with the square button), I noticed a ‘ES file Explorer’ window appeared, signaling that this app was running. However, I did not open this app. I realized then, that maybe this app caused the problem by actively drawing over other apps. As soon as I uninstalled ES file explorer, Connect Drive let me set permissions and my wireless flash drive worked flawlessly.