SolidWorks: Equation Syntax Problem

I’ve been having a tiny, yet very annoying problem working with SolidWorks 2016 lately. Now I seem to have found a solution I would like share:

Problem

sw_syntaxerror01I am using a text file with equations to propagate global variables to the parts of my model. In general that works really fine. Yet in some parts it occurred that some variables were not recognized. Trying to solve the problem, I disabled the link to file (no effect) and tried to change the value (no effect either). SolidWorks kept on telling me:

The syntax of this equation is incorrect.sw_syntaxerror03

which is clearly wasn’t. I searched for similar problems and found some people having problems with the internal VBA execution of SolidWorks, that in some cases failed after a Windows update. Fortunately my problem finally was not that severe.

(running SolidWorks 2016 Standard SP 4 x64 Edition on Windows 10 Home)

Fix

After a lot of trying around I noticed that the problem occurred only in parts whose unit was set to inch. Now the imperial system in itself is a terrible mistake (how much is 17/32 of a barleycorn again?), but it usually does not cause errors in CAD-programs. In this case however, turning the parts unit to millimetres (Options –> Document Properties –> Units –> MMGS) and a subsequent opening and rebuilding of the Equations-window in the tree will resolve the issue. 

By the way, for those who think in hands, inches and poppyseeds: switching back the part to imperial will not cause the problem to return.