I have a Samsung Galaxy S5. The problems I’ve had lately are WiFi will not enable and slow running. I have downloaded the Upgrade Assistant to repair the software to see if that will work before I have to do a factory reset.
After downloading the software and installing, I connect the phone, click on Repair Assistant, select the phone, click on Repair and then Backup. After it seems as though it has backed up the phone, I click on Repair. It begins and says Downloading Software. After 25%, the repair ends and reverts back to the Repair button. I am connected to the internet on my Mac.