In the past, we’ve always recommended that clients hire a locksmith to install locks on both the top and bottom of sliding doors to help deal with this risk.
I came across a much cheaper, do it yourself, solution for this issue on Shawn Flaugher’s blog.
“A washer screwed into the top part of the door that prevents it from being raised any higher then the side of the washer protrudes from the door’s edge.”
Click on the image to get a bigger version that’s a little easier to see.
Shawn is a Security Consultant in Raleigh, North Carolina and his blog has a lot of great content… especially for commercial and industrial properties.