Will a 7mm SSD fit in a 9.5mm laptop HDD slot?

Yes the 7.5mm, 9.0mm will fit into all 2.5" standard SATA bays, because the side screws will align the SATA port to the port on the motherboard. The same applies for thicker HDD's - but not all thicker ones will fill ie- wont be possible to screw the cover back on.

It is highly likley (only on some models of Acer do not use this) that there will be a caddy. You will need to put this on the SSD to maintain the correct alinement's and avoid damage to SATA port.

Then the cover that goes over the HDD bay, will usually keep the cradle in place, stopping the drive from falling out of the connector.

P.S.: Enjoy the SSD. I love the speed improvement, especially on loading apps and games. Amazing!

P.S.S: Recently I tried to fit a 9.0mm into a Dell netbook type thing. It did fit, just but the lid did not close and then I noticed the dell connector did not slot in. So please check in the manual to absolute sure that it will accept a 9.00mm

This is a good discussion - just one thing to add:

In Dell Precision laptops, I've found that the secondary drive bay works really well for BOTH the 7mm and 9.5mm drives but the primary drive bay doesn't. But, NEW Dell machines are shipping with a ~2mm rubber spacer.

So, why many systems do work - when the drive is screwed in (like in the secondard drive bays) it doesn't work as well in the primary. I had to create a shim (which I did out of some left-over "pluck and pull" foam from a Pelican case).

I wish the rubber spacers were easy to find though. I'd have bought one for sure!

hth, k