Shortcuts using Shift have stopped working

[elitsa_n]

Hello!

I'm using Photoshop 2022 (v23.5) and have been for a while. Today when trying to "Save as", I realised that Ctrl+Shift+S was no longer working. I thought that was a bit weird but oh well. Later, I tried to merge all visible layers (Ctrl+Shift+E)... also not working. Inversing a selection (Ctrl+Shift+I) doesn't work either. In the meantime Ctrl+S, Ctrl+I, Ctrl+E all work as they should. 
For reference, I have my preferences set to use "Legacy Save As", have had this for ages and haven't had any problems with Ctrl+Shift+S before but thought it's worth mentioning. I tried Alt+Ctrl+Shift+S ("Export As") and that didn't work either! 

Without shortcuts, these actions (saving as, inversing selection, merging visible layers, etc) all work fine, so it's not like Photoshop just refuses to do them, just doesn't recognise the shortcut.

My keyboard shortcuts are the default ones, I've never changed anything around - I did check and they're all as they should be. My Shift key is working just fine (in fact I'm using it to capitalise letters in this post lol!). I've tried using both Shift keys on my keyboard to confirm this, neither one works. The only other thing I could think of is checking my keyboard language - sometimes I accidentally shift between English UK and US and that affects things like pressing/holding ` to set the brush mode to "clear". I've tried both UK and US and neither worked. 

I haven't found anything similar mentioned on here and I'm out of ideas to try so... can anyone think of anything?

Thanks in advance!

[CShubert]

Hi @elitsa_n 

Let's make sure we're in a default state and there are no stale settings somewhere: 

Restore your preferences using this manual method:  

https://helpx.adobe.com/photoshop/using/preferences.html#Manually  

Does it work correctly? 

If that doesn't solve it, you can quit Photoshop and put the Settings folder back.