Context:

I have an NVR-8580 that records from multiple cameras. It is connected to the Swann Video Management Software, running on Windows 10. The software handles recording, and the NVR basically just acts as a POE switch. Typically, all my cameras are set to record continuously 24/7, using the same strategy which records the mainstream with a switch file interval of 30 minutes. This results in files which look like this:

NAME_OF_CAMERA_20230917010003.mp4

NAME_OF_CAMERA_20230917013003.mp4

NAME_OF_CAMERA_20230917020003.mp4

Each of these files is approximately 245 MB in size.

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Problem:

Last week, for no reason that I can discern, the VMS started recording videos of approximately 4 hours and 19 minutes in length, with a file size of approximately 2.1 GB each. For each camera, the first filename follows the same naming convention as above, then subsequent ones look like this:

NAME_OF_CAMERA_20230917200022_2023-09-18-00-19-41.mp4

NAME_OF_CAMERA_20230917200022_2023-09-18-04-39-06.mp4

I only discovered this after a later power failure. When we rebooted the system, new recordings were back to normal (as described above, 30 minutes, 245 MB). I can't find anything in the configuration menus that would have caused this. The 2.1 GB files even seem to run counter to some of the established settings: besides the 30 minute switch interval, I also have File config » Max File Size set to 1G.

Any idea what caused this, or how I can prevent settings from changing again?

Thanks!