Hello
1 - Since the .340 version, when I click on the button Restart (changes of an option in edge://flags/)the browser closes but does not reopen (the Edge process is still running in the task manager)
2 - Possible to re-put the option to disable the immersive reader (as it was before) in edge://flags/ (or in edge://policy/ )
Easy to set up and everyone is happy 
3 - If "Browsing history" in edge://settings/clearBrowsingDataOnClose is enable, it causes the bug to have about:blank page when we open Edge before having the requested web page (shortcut, start page, clickable link, etc ...)
If the browser is already open, and I open a web page from a shortcut, clickable link from software, etc... I have the requested page directly in new tab (no about:blank)
4 - Always display bugs in text frames or clickable buttons of some sites
Thanks for your great work
@tistou wrote:
My start page is www.free.fr
and about: blank appears for any web page
Even if I put the link of this forum for the start page, I have about:blank first
No problem if I put "new tab" for the start page, there is no url
I tried it and couldn't reproduce it. Edge canary opens the page normally, no about:blank
this can't be a bug that is only happening to you because that wouldn't be a bug at all.
for these reasons:
1. If this was a Bug that was caused by controlled feature roll outs, which is the only factor that differentiates our browsers, it should have got fixed by itself by now.
look at the date, posted 11/22. it's 1/7 now. whatever experiment that was going on at that point in time is finished now.
2. there are most likely lots of people that set a custom page to open on startup instead of the NTP. it's a common thing. but there hasn't been any reports in the forum about this issue. can't be that everyone else is clumsy and you're the only one who pays attention :)
I also tried setting my Edge language to French, in case it was only happening to that locale, and using VPN to get French IP address, but still nothing, it was working normally.
What's the version of your Windows 10?
it says Edge beta 79, but you already said it doesn't have the problem of blank page on start up.
test it on a virtual machine, clean install of Windows 10, with newest Edge insider canary 81, that is where the problem is happening like you said. don't configure anything, neither in Windows nor in Edge, only set the URL to open at startup in Edge settings.
a video recording would also be appreciated
btw when i said i was using French IP to test Edge canary 81
@Deleted
No change with the latest version of Canary
With the latest version of Canary, the option "Microsoft Edge Reading View for Selection" was added.
You could have (re) added at the same time the option to disable the immersive reader