Because of the methods MaxTo uses for achieving its functionality, some programs may be partially or completely incompatible with MaxTo.
The compatibility shims disable or alter specific MaxTo functionality for the affected programs to prevent the program from crashing because of MaxTo. In some cases you won't even know that a program has some functionality missing, but for others (such as Adobe Acrobat Reader) no MaxTo features work.
Usually this is because some sort of security feature in the affected program that we cannot work around.
Some of the shims provide workarounds to the problem. If that is the case, you can disable the compatibility shim for that program easily. The description for each shim will let you know if this is a possibility, and what you need to do to make it work.
We maintain an up-to-date list of compatibility shims here on this website.