It's time for a clean install of my Windows 10 pro. I intend to format the SSD drive that is used for the OS and then install Win 10 again (I use a seperate HDD for storage) When choosing a location I see that there are three partitions on the SSD (Drive 1):

Windows setup

Partitions number 1 and 3 are most likely system reserved partitions. I know this for sure about Drive 1 Partition 1. I have two questions about this situation.

  1. Can I also format and/or merge system reserved partitions if I intend to do a clean install?
  2. Is it possible for Drive 1, partition 3 to be a system reserved partition from an earlier installation of Windows? Can I also format and merge this?
  • 2
    Disconnect any extra drives you have that windows is Not being installed on. Now delete partitions on the target drive, then hit next button to install windows, it will create any partitions it needs during installation. Re-connect the other drive after windows is installed. – Moab Sep 30 '19 at 20:17

Yes, you can certainly delete the System Reserved Partitions as Windows re-creates those partitions during a clean install.

Best practice is to Delete all of the partitions on the drive you intend to install Windows on, leaving a single un-partitioned space for the drive, ensuring the cleanest experience. Windows will handle everything else.

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  • So delete all three partitions on the SSD (drive 1)? What is the advantage of deleting over formatting? That it creates one unallocated partition for the clean installation of Windows? – Iarwain Sep 30 '19 at 20:29
  • @Iarwain correct, it keeps things simple, plus by formatting ahead of time, you're adding another layer of (minor) data security in terms of an extra format/wipe. – studiohack Oct 8 '19 at 17:20

You should identify all partitions. It appears to me that Partition 3 is your vendor's OEM recovery partition. I would not delete that for sure.

You may, in fact, wish to use it to recovery your machine to factory specs.

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  • Partition 3 isn’t large enough to be an OEM recovery partition. It cannot possibly contain the required image. It however, is indeed the WinRE partition, which will be automatically be recreated if the author were to delete all partition and install Windows 10 on the disk containing a single unallocated partition. – Ramhound Sep 30 '19 at 21:48
  • It depends on the contents. My recovery partition (two machines here) is 950 MB – John Sep 30 '19 at 21:50

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