After installing Outlook's January 2018 update, some users are unable to edit signatures.
Microsoft has identified the cause as having both the Windows app store version installed as well as a "normal" version. This would be the case if you have a new computer and Office was preinstalled, then you installed your own copy of Office.
After uninstalling the Windows store app the Signature or Stationery and Fonts button should work.
- Open Settings, Find Apps & features.
- Click on the Office Desktop App and select Uninstall
- A second small Uninstall dialog will open, for you to confirm.
Stationery and Fonts button is grayed out
This is the original cause of the buttons not working and dates back to 2012.
A fairly common problem for 64-bit Windows users is that Outlook's Stationery and Fonts or Signatures buttons won't work.
First, empty your Temporary Internet Files. This may or may not help much, but even if it doesn't do any good, your Internet cache will be clean.
Empty your temp internet files and if it still fails, change both (Default) and LocalServer32 values in each of the following keys to the appropriate path for your installation of Outlook.
Default installation paths for Office / Outlook are:
Outlook 2016 Subscriptions & Retail Licenses 64-bit:
C:\Program Files\Microsoft Office 16\root\office16\Outlook.exe
Outlook 2016 Subscriptions & Retail Licenses 32-bit:
C:\Program Files (x86)\Microsoft Office 16\root\office16\Outlook.exe
Outlook 2016 ProPlus (volume license) 64-bit:
C:\Program Files\Microsoft Office\Office16\Outlook.exe
Outlook 2016 ProPlus (volume license) 32-bit:
C:\Program Files (x86)\Microsoft Office\Office16\Outlook.exe
Outlook 2013 Subscriptions & Retail Licenses 64-bit:
C:\Program Files\Microsoft Office 15\root\office15\Outlook.exe
Outlook 2013 Subscriptions & Retail Licenses 32-bit:
C:\Program Files (x86)\Microsoft Office 15\root\office15\Outlook.exe
Outlook 2013 ProPlus (volume license) 64-bit:
C:\Program Files\Microsoft Office\Office15\Outlook.exe
Outlook 2013 ProPlus (volume license) 32-bit:
C:\Program Files (x86)\Microsoft Office\Office15\Outlook.exe
C:\Program Files (x86)\Microsoft Office\Office14\Outlook.exe
Don't forget to restart Outlook after editing the registry.
Do it for me
To open the registry editor, press Windows key + R to open the Run command. Type regedit into the Run field and press OK to open the registry editor.