Suddenly can't run video from web (YouTube) or local .mp4 files
All was well until one day my iMac would not stream videos, such as YouTube, or .mp4 files already on the hard drive. The first frame of the video will show but will not run. If I click along the progress bar I can see the correct frame for that point on the progress bar. I've tried 3 different browsers and have 715Mbps download on Optical Fiber Internet. But because it also will not run local .mp4 files I don't think it's the web's problem. When I click a link to move to another web page I get the little spinning pinwheel and sometimes a blue box telling me to wait. If I click the WAIT the new page will eventually load and show but still won't run video.
I'm so frustrated I don't know what to do. This happened overnight with no changes made to any configurations. HELP!! I have what I guess is considered an outdated machine but can't afford a new one.
Comments
If it's an old iMac earlier than 2015 and has a hard drive rather than SSD, it may be in the process of failing. Hard drive lifespan is around 8 years. Disk Utility in /Applications/Utilities can check for some drive errors. This check won't always detect hardware failure.
If you don't have a backup of the drive content, it would be a good idea to set one up. The drive can be replaced if it's failing but it's also possible to boot from USB. This is one way to check if it's the drive. Portable SSDs like this would work:
https://www.amazon.com/Samsung-T7-Portable-SSD-MU-PC1T0T/dp/B087DFLF9S/
Clone the whole system to it, including boot drive using software like the following:
https://bombich.com/download
Then you can boot from the drive holding alt-key and see if files load ok.