Is it bad to place a HDD upside down?

[a04771]

I'm currently using a WD 1TB HDD. Is it bad to place a HDD upside down?

 

[Ironsounds]

Hello... NO... side mount is another option too... and is typical in external HD enclosures.

 

[Chugalug_]

Doesn't matter.
99% of manufacturers say that as long as it is at a conventional angle and is stable, aka any position that can be achieved horizontally, vertically, diagonally, or in any orientation of the drive, just so long as the drive is not positioned on its sides, and is flat. (sideways, upside down, right side up)
Western Digital is one of these manufacturers.
Ideally however you want to put it right side up, however it doesn't affect performance.
EDIT: http://www.wdc.com/wdproducts/library/other/2579-001027.pdf
See page 10 of the manual, page 12 I think in the PDF.
As long as the drive is stable and screwed in, no worries.
Here are the responses from manufacturers in this regard.

Hitachi:
The drive will operate in all axes (6 directions). Performance and error rate will stay within specification limits if the drive is operated in the other orientations from which it was formatted.

Western Digital:
Physical mounting of the drive: WD drives will function normally whether they are mounted sideways or upside down (any X, Y, Z orientation).

Maxtor: The hard drive can be mounted in any orientation.

Samsung: As long as it is securely attached to the chassis, hard disk drives may be mounted either horizontally or vertically depending on how your computer’s case is constructed.