Why disconnect the HDD when installing OS on SSD?

[xxaamxx135]

I was just wondering, why is it necessary to disconnect the HDD before you install Windows onto the SSD? I had Windows 7 and upgraded to 8 pro but I did it with my HDD still installed. I have a feeling it has to do with where the boot files are stored but I really have no clue.

 

[Seladon-1370374]

It's just to make sure that the OS installs on the SSD and not on the HDD. I personally installed my OS with both my SSD and HDD on, and it still worked.

 

[Sakkura]

Yeah it's not strictly necessary, it's just an easy thing to do to make 100% sure you don't have to redo the install or fiddle with it.

 

[USAFRet]

Also, Win7 & 8 create a 100MB System Reserved partition. Boot information. If two drives are installed, it generally creates that on the second drive. So if you ever want to repurpose that drive in another PC, or if it dies....then there is no boot info.

Having just the one drive installed forces that to be on that particular drive.

 

[JackNaylorPE]

Same reason ya turn off the circuit breaker when ya change out a light fixture ..... prevents costly mistakes

 

[13thmonkey]

Also, Win7 & 8 create a 100MB System Reserved partition. Boot information. If two drives are installed, it generally creates that on the second drive. So if you ever want to repurpose that drive in another PC, or if it dies....then there is no boot info.

Having just the one drive installed forces that to be on that particular drive.

+many windows placement of the 100MB system partition is not controllable and can be a bit wayward, especially if there already is one on one of the drives in question.

 

[WinOutreach2]

The placement of the system reserved partition is controllable, but only using command line or Windows deployment tools like the Microsoft Deployment Toolkit or Answer Files created through the Windows System Image Manager. It is easiest for a single build just to ensure that the only drive in the system is the one on which the operating system and associated boot partitions are to be located.

It can also help to have any card readers or optical drives you are not using unplugged at the time of installation as well, to prevent them from receiving drive letters. That way you can plug in each device in the order you want and receive the next available drive letters, D:, E:, F:, etc. though if you are installing from optical disk, that drive will be required and will end up with D:, luckily, the drive letters are at least easy to change from within the operating system.

Same reason ya turn off the circuit breaker when ya change out a light fixture ..... prevents costly mistakes

Also this. If there is data on the second drive, it is far better to be safe than sorry.

 

[dodger46]

I've found that installing W8 to Unallocated Space by deleting all partitions on the target drive guarantees a 350Mb System Reserved Partition being created on that drive...(But I still disconnect other drives!)