Hello,
I have 2 computers in network: a laptop that contains BIAB and that I use with my keyboard, but whose HD is too small to contain the Realtracks. So I installed them on my desktop but BIAB tells me that the folder does not exist. Is it necessary to go through an external hard drive?
Thanks to all

No. Did you go into Preferences, RealTracks and use the Custom location to point to where the RealTracks are?

Your mention of a network makes me wonder, did you copy the RealTracks to a networked drive, or to a hard drive in your desktop?

Either way, you would probably need to map the drive to a drive letter on your machine so you could put the mapping in the BIAB/real band preferences.

Yes I go into Preferences, RealTracks and use the Custom location to point to where the RealTracks are.
The RealTracks are on the Hard drive of the desktop.
Windows 10 see the folder and can open it.
In BIAB, when I use Options/Préférences I can see the folder RealTracks but BIAB anwser: "The folder "\\PC-BUREAU\RealTracks" does not exist"
PC-BUREAU is the name of the desktop.

I hope you can understand what I'm wriiting because I am french and my English is really bad.
Thank you

Take \\PC-BUREAU\RealTracks and map it to a drive letter in Windows Explorer. (E, F, G or any letter).

Then you can go to Option/Preferences and choose the drive letter you set.

To do the above suggestion;
Go to File Explorer (or Start works also)
Right-Click 'Computer'
Select -> Map Network Drive

Paste in the location, pick a drive letter and save.

This works well on Windows, but on Macs it doesn't 'stick'. You have to make it part of your profile on Mac so it loads every time you log on.

I find!
If I map directly the folder RealTracks BIAB does not accept.
I need to map the folder that contain RealTracks, for exemple:
Z:\Music\Realtracks and then BIAB accept.
Thank you very much everyone.