Open cc_config.xml
Change <dont_use_wsl>0</dont_use_wsl> to <dont_use_wsl>1</dont_use_wsl>
If there is no <dont_use_wsl> entry you need to change logging options from boincmgr and cc_config.xml will be populated with default options.
I only heard about one wsl test on gpugrid. Nothing came out of it.

Yes we can turn on better logging, but for that we need to increase your output file via cc_config.xml because with the logging function on the default 2MB is filled almost instantly. I'm sure if need be we can do that. But I don't think it's needed. Your startup log shows enough: your BOINC client is stuck in a boot loop, apparently crashing before getting through the whole loop, and restarting. This is why BOINC Manager cannot connect to the BOINC client, because, well, there is no BOINC client to connect to because it has crashed. I think due to the stuck WSL process taking up all CPU cores.

Seeing as how you fixed the problematic WSL startup process, we could think that fixed it.
My advice is to retry to reproduce it now, with the fixed WSL startup process, and see if you can do it again.

If not, it's down to that and doesn't really need an additional fix at this time.
If you can reproduce it now, we can think of adding a delayed startup of the BOINC Client & Manager.

As you can see there's a pile of information about what has started, how things are configured. The easiest way to get this is very soon after a re-boot of the computer, say five minutes, or (as in my case) have a very large event log.

Depending on the number of projects and total number of file in the projects data folders, it can show for several minutes the "waiting message", before it disappears and you have control of BOINC.

You need to get the first 30 or so lines from the stdoutdae.txt FILE located in the BOINCDATA folder a few minutes after BOINC is restarted, not from the ,BOINC Manager console. The file is by default located in C:\ProgramDats\BOINC\ which might be a hidden folder.

Use a text editor to open the file such as notepad.exe

Highlight the first 30 lines, copy and paste into a new message in this topic and post your reply.

Okay, before we give you the runaround on paths and such, let's just first focus on the message. "Connecting to localhost" means that BOINC Manager (the GUI) has started, but the BOINC client may not have, or it is too busy starting up tasks, loading them in memory, to immediately connect with BOINC Manager to show what it's doing.

Keith told you to open Task Manager and kill the BOINC Manager process, instead I want you to open Task Manager and see if both boinc.exe and boincmgr.exe are running in the Processes tab. If only BOINC Manager is running, that means the client hasn't started. In that case restart the computer and see if that fixes the problem for now, then open BOINC Manager -> Options -> Other options... -> General, make sure "Run Manager at login?" and "Run the client?" are checked, then press Save and maybe that just already fixed it.

If both were already checked, then can you please tell us which projects you have added and which ones have work, and what kind of work?
Can you also give some details about your computer, or better yet, post the first 30 or so lines of the BOINC Event Log (CTRL+SHIFT+E)?

Let's just start there. Adding start delay and other fancy options to cc_config.xml is always an option, but it shouldn't be necessary for geenral users.

Where do I type in "run boinc.exe" ?

click on start, then type in

boinc.exe

Next time it happens, the first thing to check is "Which BOINC components are actually running?".

Open the Windows Task Manager. You should see three BOINC programs running:

• boinc.exe
  
• boincmgr.exe
  
• boinctray.exe
  

boincmgr.exe is the thing you're looking at; boinc.exe is the thing it's trying to connect to; and boinctray.exe you can ignore (it's a small, invisible, helper application).

It sounds like boinc.exe isn't running. There are controls in the BOINC manager ('Options' menu, 'other options...'): make sure they're set the way you want them: otherwise, something external like an anti-virus program may be blocking it.

You could open Task Manager and kill the Boinc Manager process. Then restart the Manager. Normally reconnects on the second try.

You could try setting a delay in the startup so that system processes have settled before starting the client and Manager. Try 30 seconds. Parameter is in the cc_config.xml file.

<start_delay>0.000000</start_delay>

The only workaround I've found so far is to restart my PC, but that is annoying to do everytime I just want to run Boinc. Any ideas how to fix this?

run boinc.exe

should start the client without your having to reboot.

But, worth following the other two replies which potentially lead to resolving the problem rather than just finding a work around.