Fixed:--SharePoint Designer 2013 Crashing on Open Site

The Problem

When I installed SPD2013 on my laptop, all went well. However, every time I tried to use the Open Site dialog, it would crash. SharePoint Designer 2010 (SPD2010) was still working fine when I accessed other 2010-based installations, but not SPD2013.
I found a fix that worked for me in the Technet forums. You may or may not want to trawl through the thread, as it is quite long. Instead, here’s the Cliff Notes version of what worked for me.

You can repair your SPD 2010 to restore the regkey for SPD2010.
The issue might happen in case the ClientGUID of the Open Site dialog in SPD14 is the same as the one of the open site dialog in SPD 15 in a certain Side by Side environment.
(this repro’s only in a specific environment, but I couldn’t find the enviroment yet and when the GUIDs could be the same)
so I have couple of questions. Sorry to bother you, :(
1. Could you please check if ClientGUID value under HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Common\Open Find\Microsoft SharePoint Designer\Settings\Open Site is the same as the ClientGUID value under HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Common\Open Find\Microsoft SharePoint Designer\Settings\Open Site?
2. If the values are the same, could you please check if the crash still happens after removing both registry keys?
3. Have you ever installed any other version of SPD15 on your machine? (e.g. beta version) or any other version of SPD14?
4. if the issue still happens at #2, how about removing the registry key HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\ComDLg32\LastVisitedPidlMRU ?

Points 1 and 2 did the trick for me. Apparently both SPD2010 and SPD2013 had the same GUID for the ClientGUID value in the registry. I had not installed any betas of SPD2013 on my laptop because I was concerned about exactly this sort of incompatibility. (I’d limited my use of SPD2013 to launching it inside virtual machines.)

The Fix

If you have this problem and want to fix it, here are the steps.
Open the Registry Editor. You can do this by going to the Start menu (I’m still a Windows 7 stalwart, so I can’t vouch for how this might work on Windows 8), choosing “Run”, and typing “regedit” in the Open: box.
Look for the keys:
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Common\Open Find\Microsoft SharePoint Designer\Settings\Open Site
and
HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Common\Open Find\Microsoft SharePoint Designer\Settings\Open Site
In my case, they were identical, as shown below.
SharePoint Designer 2010 (14.0)

SharePoint Designer 2013 (15.0)

Delete both of the ClientGUID keys. You can do this by highlighting the key and hitting the Delete key or right clicking and choosing Delete.
Once I had deleted these two registry keys, I was able to open sites in both versions of SharePoint Designer with no problems.
Unfortunately, the two versions of SharePoint Designer seem to use the same recent sites list, so I see the same Recent Sites in both versions. This is going to make it confusing when I am trying to figure out which site to open. Now I’m a three SharePoint Designer version guy, as I’m still using SPD2007 and SPD2010 for client work in addition to SPD2013. Yeesh.