I was asked to look into an issue where the Euro symbol (€) would refuse to be inserted when pressing AltGr+E (the default key combination for the symbol on a German keyboard).
Both in Word and Outlook, pressing the key combination has no effect. The client assured me that the issue is global (affects all applications). Upon first inspection of the notification area, I couldn't spot any applications that I would suspect of causing this.
The E key works just fine otherwise. The AltGr key seems to work as intended as well. Pressing AltGr+M will print a µ for example. So stuck keys are unlikely.
The active keyboard layout is set to German, so that shouldn't be an issue either.
The client told me that it worked just fine in the past and that he already switched keyboards to no effect (and I believe him).
I was only be able to use the system briefly and couldn't troubleshoot the issue further (for today).
Best Answer
The problem was caused by a telephony client application running on the same computer. I didn't think it could be an issue until I called the client to troubleshoot the issue.
When I asked him to try to type the Euro symbol, suddenly our call ended. When it happened again, I assumed we're on to something.
Sorry for the localized screenshot. The highlighted part says End call: