I have a CNC router running a Uno board with GRBL 1.1. I just obtained a Mega 2560 to use on a CNC laser machine. When I try to add the GRBL version for the Mega, Arduino gives a message that there is already a GRBL folder in the library. I would be grateful for instructions to add the second GRBL version for Mega.
Whilst it is possible to use two different versions of GRBL on the same machine (using PORTABLE IDE installation)
It may be better is both use the same version as they will still show on different COM ports
1.1 If about the latest and is very very stable.
It also has some benefits over other versions and more so for laser work.
Most of the Chinese boards were supplied with older version so upgrades are worthwhile.
As you discovered, you can't have two versions of the same library installed at the same time.
There are a few workarounds for this. The workaround of having two completely separate installations of the entire Arduino IDE mentioned by ballscrewbob is one of them. I'll mention another that is perhaps a little more simple and easier to maintain:
The libraries you install are installed to a special folder called a "sketchbook". You can configure the location of the sketchbook in the Arduino IDE at File > Preferences > Sketchbook Location. So you can use one sketchbook location for the installation of the Uno's version of GRBL and another sketchbook location for the installation of the Mega's version of GRBL, then be sure to select the appropriate sketchbook location in the preferences before uploading GRBL to each board. Keep in mind that any libraries you install to one sketchbook will not be available when you are using the other sketchbook.
I found that by renaming the GRBL for the Mega, I could have two different versions on the one sketchbook. I changed the file name for Mega GRBL to GRBLv1 and was able to add it to the library.
This accomplished what I wanted.