Yurtles wrote:I hadn't thought to look at my bios before now (Why would I? I never touched any settings in it and never put a finger on my case) but it looks like my HDD was showing up in the bios on some boots and missing on others. If it was coming and going like that while in windows that'd explain what I'm seeing as easily as some weird sleep/power management thing.
I suggest backing up any data on that HDD just in case the HDD has an issue.
If the HDD is attached to a non-Intel SATA controller I'd be moving it to the Intel SATA controller as I have seen detection issues on non-Intel SATA controllers, if you do swap SATA ports be sure to check storage boot priorities.
Sometimes updating firmware on non-Intel SATA controllers resolves issues but can also brick the SATA controller if the flash goes bad or introduce other issues.
Non-Intel SATA controllers also often require their own drivers from the OEM for optimal interoperability and/or performance and/or reliability.
Yurtles wrote:I swapped the SATA cable out for a different one as an initial test and the HDD's been solidly visible and working properly since I did it earlier tonight. Which is interesting in itself, I had all sorts of trouble with (what turned out to be) the SATA cable I had connected to my SSD when I first built this system too. Maybe I just got a bad batch of cables with my motherboard or something.
Hopefully that was the cause of the issue.
Yurtles wrote:Of course, none of this makes sense since it was working fine pre-Windows 10, but what can you do? If it's fixed, it's fixed.
It is theoretically possible that Windows 10 downloaded firmware and flashed the SATA controller the HDD is connected to which could have introduced the issue.