Additional notes:
1. The spacebar works if I change the message format from html to text.

https://outlook.office.com/owa/?realm=yourcompanyhere.com&path=/options/messageformat

2. If I try to run the previous Chrome version by renaming the exe's in the install folder:
Chrome.exe     //( 53.0.2785.30 )
Chrome-new.exe //( 54.0.2810.2 )
I get the following error:

The application has failed to start because the side-by-side configuration is incorrect. Please see the application event log for more details.

The site needs a valid credentials to triage it.Please let us know if there is any shareable test account to triage further.

Have tried in OutlookWeb App of my corporate account and was unable to reproduce the issue on Windows 7 and Mac 10.11.6 using stable 52.0.2743.82,dev 54.0.2810.2 and canary 54.0.2816.0.Attached screen shot for the reference.

Deleted: 633284_Aug_2.png 41.6 KB

	633284_Aug_2.png 41.6 KB View Download

Adding Restricted label as there might be sensitive data updates in this thread.

Yay it works again after logging into OWA on another pc and toggling message format = html. I did not reboot my pc since creating this issue.

That pc was running Chrome Chrome Version 52.0.2743.82 m.
I'm using Chrome Version 54.0.2810.2 dev-m (64-bit).

Wow, this was a problem for days?
At least no more typing replies in Notepad!!

I will close this issue after a few more days of no problems.
Thanks.

Aaannnd, it is broken again. :(
Super weird but reproducible.
I can change the message format on another pc and Chrome sync shows that on my local pc, but the actual local browser is still in text format. That tricked me to think it was actually working.

So, I am still forced to use message format = text for this version of Chrome to accept spacebar entries.

sky5walk@, 

Could you tell me what happen when you paste a space character into OWA email composer?

I would like to know which is broken, typing a space or inserting a space.

Thanks!

Yes, as I mentioned I was editing my replies and new emails in Notepad and pasting them into the OWA textbox. A single space or an entire message paste in fine.
The rejected spacebar inputs are intermittent.
I can enter spaces immediately after an Enter(CRLF).
But, any other characters resume the blocking of spaces!

I hope this is not related to the recent removal of the backspace key during browsing to signal previous web page? A most frustrating decision in Chromium development. :(

Removing the Needs-Bisect label as of now as unable to reproduce it from TE end.Please do add it if there is a consistent repro steps to further triage it.

Ok,
Version 54.0.2816.0 dev-m (64-bit) just kicked in and the spacebar works in Outlook OWA textbox with message format = html.

Thanks for the fix. 
But, I don't see it mentioned?

I've not been aware what change fixes this issue.
It is possible some changes in OWA.

Anyway, mark "WontFix" at this time. If you see this issue again, please feel free to re-open this bug.

Thanks for reporting and your patient.

for the history, it is not restricted to windows.
i've got the same issue on a debian box.

that was upgrade from google-chrome-unstable_53.0.2767.4-1_amd64.deb to google-chrome-unstable_54.0.2810.2-1_amd64.deb (there were more versions installed, but browser is not restarted that often).
downgrading back (to google-chrome-unstable_53.0.2785.21-1_amd64.deb) helped.

how the issue appears to present itself.

1. login to office 365 owa
2. start composing a message (by default it starts in html mode, i had not checked it with text mode)
3. start typing something.
4. at the very end of the line, spacebar does not work. trying to paste from a clipboard (primary/secondary) does not work.
5. however, it works in any other place of a line.

as for "is it fixed in 54.0.2816.0-1?" - not going to check unless it is known that primary clipboard works. (well, you know that, double-click on something and paste by middle click to other window - it is broken in 54.x version, selection is not copied to a buffer like at all. you are forced to do ctrl-c thing and copy it to clipboard and fill _both_ buffers.)

small correction here:

> 4. at the very end of the line, spacebar does not work. trying to paste from a clipboard (primary/secondary) does not work.

pasting from a clipboard here means "pasting a single space character, copied from anywhere". it did not help, nothing was pasted. (someone accidentally enabled trimming whitespaces at the end of the line?)


regarding clipboard - this is the  issue 634148 .