I switched to Solidworks 2013 but since then when I want to "configure the function" of a constraint the following message appears (see attached imgae).
And in the "System Options/File Locations" I don't know where the path it lost is:(
The problem is that your link talks about SW2012 and that apparently it didn't follow everything. You should go and see in windows explorer if you find a similar folder but with the 2013 determination
The problem probably comes from the update, you must have used the SolidWorks 2012 configurations for 2013.
You may have other parameter problems...
It's better to redo a clean configuration when installing a new version, even if it's long and tedious...
To see all the paths involved, you can make a backup of the settings from the start menu > SolidWorks 2013, and open the created file with a text editor (notepad++ for example).
And if you search for 2012 in this file, you may have surprises!
If it causes problems with the configuration of functions, it may cause problems elsewhere!
Go to Tools/Options/File Locations and from the drop-down menu, select the first line (even if it's already the one selected !!).
This will put your cursor on the drop-down list, and you can use the DOWN arrow on your keyboard to scroll through the entire list and see the path(s) just below.
This will quickly identify all the paths that did not follow from [/SolidWorks2012/] to [/SolidWorks/] and redirect these paths. Make the complete list, so that you don't have to ask yourself any questions later !
FYI, the problem is probably because you used your old settings (file. SLDREG). The paths are stored there.