How to disable LabVIEW checks the Grammar/Eddit Error Automatically function

[billko]

That could be a clue.  I googled xcontrol issues.  I don't know if parts of this topic are still relevant, but maybe at least part of your answer lies here.

[aptivo]

Are these many SubVIs related to classes or at least splitable in a few groups without any cross-dependencies? 

If this is the case packed project libaries (*.lvlibp) can be a solution to resolve issues with long loading time.

[API]

Dear Bill，thanks for your help/thread, yes, maybe the root of reason is Xcontrol, but it is hard for us to remove/replace Xcontrol. we may organize an expriment to check the condition without Xcontrols.