The following solution worked for me and I´m happy that it does.
First in your Web-Browser open the following link:
steam://nav/console
Click on the button "open steam" on the message that appeared.
Then download the older Version of Rocksmith 2014:
The generic command to download a specific Version i found in the steam docs:
download_depot <appid> <depotid> <manifestid>
For PC:
download_depot 221680 221681 6723575466552698766
For Mac:
download_depot 221680 221682 7701843782525516716
Then it will show you where the version have been downloaded to:
e.g.
Depot download complete : "E:\Games\Steam\steamapps\content\app_221680\depot_221681" (93 files, manifest 6723575466552698766)
Then replace the content of the Folder where the game is installed with the files of the downloaded depot folder:
e.g.
E:\Games\Steam\steamapps\common\Rocksmith2014
Then use the BeatSaber method to prevent future updates:
https://i.imgur.com/4eFUbNx.png
Here you can always find the newest manifest id that you have to change in the appmanifest file.
https://steamdb.info/depot/221681/manifests/
The appmanifest file you will find at the following location:
...\Steam\steamapps\appmanifest_221680.acf
1st:
The `StateFlags` Value have to be changed from `6` to `4` so that it will be flagged that it is allready up2date.
2nd:
The `manifest` Value have to be changed from to the newest version. You can find the latest Version here:
PC:
"AppState"
{
"appid" "221680"
...
"StateFlags" "4"
...
"InstalledDepots"
{
"221681"
{
"manifest" "8947385950072815193"
"size" "6866729152"
}
...
}
MAC: https://steamdb.info/depot/221682/manifests/
"AppState"
{
"appid" "221680"
...
"StateFlags" "4"
...
"InstalledDepots"
{
"221682"
{
"manifest" "4787497299038694780"
"size" "6866729152"
}
...
}
If you have problems with connecting to ubisoft account inside the game, hit `ESC` the first two times until you see the profile screen.
Have fun.