My best guess is that the garbage cleanup in SSMS is flawed.
I get this error repeatedly, usually under the following circumstances:
1. SSMS has been open for a long time (days...I don't usually shut down my PC at work)
2. Have at least 4-5 minimum query windows open
3. SSMS is using around 700MB of ram on my PC
At some point, even a request for just a table with a few rows of data will show this error.
Even if I close all query windows and open a new fresh window, the error still persists.
We're using SQL Server 2012 on the server, and SSMS for SQL Server 12 on local client machines.
All developers in our group have experienced this error at one time or another.
Advice to Microsoft: Once a query window is closed, clean-up memory to allow for new work to commence.