XPS 13 8.1 to Win 10 & Back - Win 10 Not Complete Gone

I recently upgraded from Windows 8.1 to Windows 10. Unfortunately, there was an incompatibility with one of my programs, so I downgraded back to Windows 8.1.

There must have been some "ghost" images or files remaining as the error that occurred after the upgrade continue.

I suspect that when I did the re-install back to 8.1, I did not "completely" wipe the HDD (SSD).

I used the USB key provided by Dell and chose the option of advanced including deleting the primary partition.

The other partitions were #1 - "System Reserved @ 350MB and #3 OEM (Reserved) @ 113MB. I did not delete either of these partitions.

From there I installed windows 8 (the original O/S) then I upgraded to Windows 8.1 then installed all the remaining Windows updates.

So, I suspect I skipped something that resulted in not completely cleaning the original partition.

Should I have deleted Partition #1 and #3 too?

 

Upgrading to (or downgrading from) Windows 10 does not affect disk partitioning at all. An upgrade or downgrade will use existing partitions, and just copy files onto those previously existing partitions.

To give you more info:
1) 350MB System Reserved - this is created by Windows to store bootloader and boot configuration information.
2) 113MB OEM (Reserved) - this is created by Dell to store diagnostic and recovery tools.

Both of those partitions will exist in any factory-configured Dell machine created since 2006, and should be there. They were not created by Windows 10, and should not be disturbed. Leave the alone. Tampering with them without knowing what you're doing will very likely cause your machine not to boot.

 

The system restored in just a little under 5 minutes. That is way to short to start from scratch.

I did remove the other petitions, but no ill effect has been noticed as of yet.

Thank you, Kent, for your response.

Regards,