Falsches Tastenkürzel fürs Objektauswahlwerkzeug

For me, the keyboard shortcut is W, on an English keyboard of course. Would be curious if your shortcut changes after a preferences reset as Cory suggests:

For tools that share the same keyboard shortcut, typically holding Shfit while pressing that key will cycle through the similar keys within the group. See if Shift+B in your case helps you select the Object Selection tool

Hi @Sven29440842wlz4 sorry you are having issues.  A couple things to try:

https://helpx.adobe.com/photoshop/kb/keyboard-shortcuts-stop-photoshop-mac.html

If none of the steps work to reset your KBSCs, 

Try resetting Prefs for the Beta:

/Users/yourname/Library/Preferences/Adobe\ Photoshop\ \(Beta\)\ Settings 

Launch BETA Photoshop While Pressing The Keyboard Shortcut

With Photoshop closed, press and hold Shift+Ctrl+Alt (Win) / Shift+Command+Option (Mac) on your keyboard and then Launch Photoshop the way you normally would.