First unplug the USB drive and make sure the HDHomeRun is working correctly without the drive.
Likely causes:
A failing or failed hard drive may cause an error and automatic reboot. If the drive is a conventional USB hard drive you should use the manufacturers test tools to test the drive using a PC or Mac computer.
A “fake capacity” USB flash drive may cause an error and automatic reboot. A fake capacity drive is a drive with a small capacity (say 1GB) that claims to be a large capacity (say 1TB).
If you are using a high performance USB 3.1/3.2 NVMe drive and the HDHomeRun log shows the HDHomeRun powered on during the recording it may be that the drive is drawing more than 1A, exceeding USB 3.0/2.0 power limits. The HDHomeRun FLEX supports USB drives up to 1A.
The HDHomeRun features a “Send diagnostic information” feature that allows SiliconDust support staff to help diagnose the problem.
Unplug the USB drive
Launch the HDHomeRun app on your Android phone or iPhone
Go into the Settings menu (click DVR to exit Live TV, then the Settings menu is the gear icon at the top-right of the screen)
Toggle “Send diagnostic information”
Reconnect the USB drive
Send an email to support@silicondust.com including the Device ID of your HDHomeRun. Or during business hours we offer phone callback support:
www.silicondust.com/contact/