Diablo2 Resurrected post edited
Diablo 2 Resurrected support requires the latest updates to both ISBoxer and Inner Space.
* For the ISBoxer update, make sure you have version 42.17.0923.1 or later. You can get the latest version via "Help->About ISBoxer Toolkit"
* For the Inner Space update, make sure you have 1.18 Build 6800 or later. You probably do at this point.
Things to know:
- Diablo 2 Resurrected does not have an in-client login screen. When first setting up your D2R team with ISBoxer, you will need to use the D2R Launcher for each Slot in order to save the "last used" account.
- There may be a performance issue on some systems that starts a very short time after the client launches. Our tests indicate that the latest graphics drivers for your system should resolve the issue!
First-time configuration for D2R (assuming prior experience setting up ISBoxer)
1. If Diablo 2 Resurrected is missing from Inner Space, it's most likely because you need to update Inner Space.... otherwise use "Add game" from Inner Space and point to D2R.exe in the Diablo 2 Resurrected folder.
2. Use ISBoxer's Quick Setup Wizard and select "Diablo 2 Resurrected" for the game to configure (the Diablo 3 setting will actually work as well)
3. Add Characters with any name, I used "Acc 1" and "Acc 2" etc, and point them at the "Diablo II Resurrected Launcher" Game Profile (not the Client profile. This no longer works).
4. Complete the wizard
5. Use the File Menu and Export to Inner Space and launch your new team (close battle.net first if it is running). Right click the Innerspace icon in the tray, right click the icon, select ISBoxer Character Sets, select your team. You will need to have launched the game at least once without ISBoxer. This sets a few needed settings.
6. Battle.net will launch once per account. For each Battle.net launched, if it signs in automatically (to the wrong account), sign out, and then sign in with the correct account for this Slot, Click on the gear icon next to the play button, then click on "APP", SET THE SECOND BOX to "Exit Battle.net completely" on game launch, MAKE SURE the LAST LINE "allow multiple instances of battle.net is UNCHECKED and click Done. After the game client is launched, the next Battle.net should appear. If it automatically signs in on with the wrong account for this slot, you will need to sign out, and sign in to the correct account. The games are started in Slot order for the Character Set. i.e. log in to account 1 the first time, account 2 for the second one, account 3 for the third, etc.
After logging in to each account, the next time your team is launched the accounts are already saved for you!
The above info was posted by lax.
I have edited it in RED to explain how i got it to work for me and in a way, me and the average joe can understand it and not programmers talk, lol

Reason: moar edits to remove the reference to switching between client profile and launcher