Outlook 2013 will not start when using WiFi ... works with Wired Ethernet

Hi, all.

OS: Windows 7 Pro, fully updated. Client: Outlook 2013.

(I have searched for related issues, but have not found anything, so am asking here - with boring, in-depth info.)

Symptom:

1. When using Outlook 2013 on a wired Ethernet, everything is normal. I am able to start Outlook and access our  Exchange server (hosted at securembox.com via www.calltower.com, FWIW), without any problems.
2. When using WiFi, when I start Outlook, it will not get past the "Loading Profile" message on the initial Outlook pop-up. Have waited 30 minutes without progress. This is100% repeatable even though all other network access is normal. Even using Mozilla Thunderbird for a POP e-mail site works perfectly normally.
3. Pressing "Alt-Ctrl-Del" and then merely bringing up the Task Manager -without even selecting anything in Task Manager - causes the Outlook pop-up to go away and Outlook 2013 then starts. Then, sometimes it locks up after it starts, sometimes it does not refresh some portion of the windows, sometimes it works normally, etc.

What I have tried so far without any success:

1. Different WiFi networks - at home, work, my son's school, even Comcast Xfiniti site at a business. No change in behavior - Outlook 2013 locks up at the pop-up in exactly the same way.
2. Wired Ethernet at home. Works perfectly. No problems with starting and using Outlook 2013.
3. "Outlook.exe safe" from a command prompt. This works fine on the WiFi networks too! But I am missing all my customizations, etc., so would prefer not to use it.
4. Scanpst on all the Outlook files - no major issues, and "repairing" everything does not change this WiFi issue regardless.
5. Disabling ALL plug-ins (which was indicated by the outlook.exe /safe success according to one site) does not solve the problem on the WiFi network.
6. Creating a new profile is something I am reluctant to try, because this causes me to have to redo a lot of stuff. I hope that is not the first thing that people here insist that I try!
7. Virus check via Malware Bytes and Microsoft Security Essentials is all normal and clean too.

One other suspicious event ... which may be entirely coincidental:

1. I think this problem started happening after a recent Office 2013 update - specifically Windows Office 2013 SP1 update that was installed on my machine on Feb 24th:

Service Pack 1 for Microsoft Office 2013 (KB2850036) 32-Bit Edition

My IT guy and I have not found a resolution for this issue in over five or six days now, so I would appreciate if people have some thoughts on the matter ... or can point the finger to the same Office 2013 SP1 update so that I can consider removing it for now.

Thanks much in advance!