M10 Docs
MuLab Plugin Installation
Download the MuLab Plugin zip package and unzip it to a new folder.
Then move the resulting folder into your preferred VST plugins folder.
Please make sure that the complete folder path towards the MuLab Plugin folder does not contain any special characters, except for plus, minus (hyphen), underscore, round brackets and square brackets.
MuLab Plugin comes as a self-containing folder.
It does not install anything on your system outside this folder.
You can move the MuLab Plugin folder after you have installed it.
You can even put it on a USB stick and carry your MuLab Plugin with you.
Of course it also depends on the host DAW application if that is also that flexible.
Windows
On Windows 7/8, it may be better not to install the MuLab Plugin folder under the 'Program Files' folder, but rather in a non UAC protected folder like C:/VstPlugins/MuTools/MuLab.
This is to avoid access problems caused by Windows' UAC mechanism.
The reason for this is that MuLab Plugin stores your user settings in a couple of files in MuLab/User/Settings.
The good thing about that is that your MuLab Plugin installation is easily movable, and can be put on your USB stick for example.
Another advantage is that you can have multiple independent MuLab Plugin installations on the same system, for example different main versions of MuLab Plugin.
Therefore it's best that the user settings are store inside the MuLab Plugin folder and thus this folder must be writable.
MacOS
Theoretically you can put the MuLab Plugin folder anywhere you want as long as it's on a writable location.
Practically the standard location is System Disk/Library/Audio/PlugIns/VST
MacOS Sierra and up:
Due to some new security "feature" in MacOS Sierra called 'GateKeeper Path Randomization' it may be that when inserting MuLab Plugin it alerts "Can't find app subfolder" or "Folder is not writable".
This is because MacOS Sierra and up heavily distrusts 3rd party apps and MacOS Sierra puts all extracted files from a downloaded zip package into quarantine by default.
Nothing wrong with MacOS trying to be secure but at least it should give the user an easy way to bypass it when the user wants so but MacOS doesn't do that.
To solve this MuTools has made a little tool called "Quarantine Remover" to remove that default Apple quarantine.
The Quarantine Remover is included in the downloaded zip package.
How to use it:
Catalina:
MuLab Plugin is not yet directly compatible with MacOS Catalina.
However there is a way to bypass the restrictions Apple dictates to its users:
See Insert User Key
See Updating MuLab
Simply delete the MuLab Plugin folder.
MuLab Plugin does not put any data outside that folder.