We experienced an odd issue recently on a new customer’s admittedly messy Windows 10 PC running Outlook 2016. We say messy because the machine had not been rebuilt since it was purchased many years ago and in those years had:

  • Been through a Windows 7 > Window 10 in-place upgrade.
  • Multiple versions of Office installed – 2010, 2013 and finally to 2016.
  • Either no antivirus/malware protection or very limited protection
  • A bunch of different applications installed/removed

Machines such as these are prone to oddities and this was no exception. We were migrating this customers entire site onto a new O365 service and so upgraded all of their existing Microsoft Office installations to the latest Microsoft Office 365 Business version – i.e. Office 2016. The entire migration ran like clockwork and as we shifted to the new platform all devices were running as expected; all except for this one.

Initially, we discovered we couldn’t configure an email signature within Outlook; whenever we went to File > Options > Mail and clicked on Signatures… to bring up the configuration window, nothing happened – no configuration window!

Upon realizing this, we tried clicking on a few other arbitrary Outlook Options and soon realized many of this too weren’t bringing up the appropriate configuration window, instead choosing to do absolutely nothing instead.

We tried the usual things:

  • Office Repair via Programs and Features
  • Creating a new Outlook profile via Mail in Control Panel

Neither of which provided us with a solution and so prior to completely uninstalling and reinstalling Office 365 Business – which unless you use ODT requires using click-to-run and downloading 2GB+ of data – we decided to quickly scour the web to try and find an alternative solution.


1. Open regedit – press Windows Key + R to bring up the run dialog box, type regedit and hit Enter to open the Registry Editor


2. Within the Registry Edit navigate to either of the following depending on your Office installation type:

32bit – HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{0006F03A-0000-0000-C000-000000000046}\LocalServer32

64bit – HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{0006F03A-0000-0000-C000-000000000046}\LocalServer32


3. In the right pane of LocalServer32 key modify the registry string named (Default) type REG_SZ and change the value data to one of the following depending on your Outlook version:

Outlook 2013 32bit – C:\Program Files(x86)\Microsoft Office 15\root\Office 15\OUTLOOK.EXE
Outlook 2013 64bit – C:\Program Files\Microsoft Office 15\root\Office15\OUTLOOK.EXE
Outlook 2016 32bit – C:\Program Files(x86)\Microsoft Office\root\Office16\OUTLOOK.EXE
Outlook 2016 64bit – C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE


We found that depending on your version of Office you may also find the required OUTLOOK.EXE file in the following path, at least for Office Professional Plus 2013 64bit:

C:\Program Files\Microsoft Office\Office15\OULOOK.EXE

Once you’re done with this close the Registry Editor and restart Outlook – your problem should by fixed! If you find you have any issues, try restarting the machine and reopening Outlook.

We came across an article which stated you should also modify the registry string named LocalServer32 with the exact same value data as (Default), however it appears you only need to do this if it is of the type REG_SZ. On both our test machines our LocalServer32 registry string was of the type REG_MULTI_SZ which does not contain a file path in the value data.

Article By Techzilla