This time, the reboot fixed it. For now.
This system is running windoze 7 (fully patched), Malwarebytes (fully patched), and Studio1 (last version).
The recordings are saved to a 6 TB SATA HD drive, 5200 RPM, IIRC. That should be sufficient and usually is.
Studio1 is set to save a 1 hour file (which is 14 seconds just over one hour, when things are normal).
A year or so ago, I would see an occasional disruption in a recording. The start of the recording is fine, then sometimes something would disrupt and cause the rest of the file to have scattered decodes. The new file starts fine and could continue fine. Did some troubleshooting and thought it was due to fullness of drive & fragmentation. About 5-6 months ago, cleaned off the storage drive and quick formatted it. That should've cured problems until it got full. It was fine for a while, then started happening again. So apparently that wasn't it.
The recent problem of starting out scattered and becoming good is puzzling, as that's the first time its corrected itself while recording a file.
The only thing that has changed is Malwarebytes. There was an update some number of months ago, and after that it seemed to get scattered more often than not (but I have RFI here, so I attributed it to that). Then a few days ago, another update, so I applied that and things got much better up until this strange behavior. So I rebooted, then turned off a couple of the features that I wouldn't need (this machine solely records from Studio1 and literally does nothing else). So far since the reboot its been ok, but hasn't been close to long enough.
I'm not yet ready to blame Malwarebytes. That hasn't always been on there, but can't remember if the behavior started before it was installed.
Thanks for letting me know that my behavior isn't unique... neither to the OS and it happens with other software.
I wouldn't use a USB HD unless its USB-3.
I have the full disk scan run at 1400 local time, as that's the middle of the afternoon with no more DGPS stations (and when the U.S. were still on, would only have 3 locals and sometimes some daytime DX, rarely).