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DJ_Arch's avatar
DJ_Arch
Copper Contributor
Apr 26, 2022

Office 365 won't download email with Cached Exchange switched on and connected to ethernet

So I am a sole-proprietor and have used Outlook 365 Exchange for years with no problem. I am running Windows 11 (all updates) and just recently, Outlook would stop receiving or sending any email and ...
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Paragon06's avatar
Paragon06
Copper Contributor
Apr 28, 2022
Outlook has been having issues with cached exchange mode since around the middle of feb and is effecting different people at differnt times. We found it seemed linked to an update to outlook (sorry i cant remember the version), we ended up rolling back to the previous version.

99% of the time the issue was resolved by turning off cached exchange mode, restarting outlook and then turning it back on. It worked fine then. We were happy to leave Cached exchange mode off, but then found some outlook features like notifications dont work.

For users where this didnt fix the issue, we simply deleted their outlook profile and created a new one and it also fixed the issue.

- Open Control Panel
- Go to Mail (Microsoft Outlook)
- Click Show Profiles
- Click Add
- Create new profile and then set "use this profile" to the new profile and then open outlook.

We tended to delete the old profile, but you can test the new one works properly first and all your mails sync etc first.

Hope this helps.
  • DJ_Arch's avatar
    DJ_Arch
    Copper Contributor
    May 02, 2022

    Thanks for your reply. I would have responded sooner but I am still trying to work through some problems. I have tried turning cached mode on and off as you suggested and the problem continues. And as I think I mentioned previously I had already tried creating a new user profile and that made no difference either. But I think this may just be a network driver error that has suddenly decided to surface after being stable for so long and has manifests in Outlook most prominently. As the problem continued I uninstalled the NIC driver and let Windows install whatever one it wanted. That seemed to help a bit but wasn't the cure since anytime cached mode was on Outlook wouldn't send any emails. And I really focused on the NIC since if I used the motherboard's wi-fi adapter (turning off the NIC first)everything in Outlook worked just fine. So it had to be some way that the NIC and Outlook were communicating with each other that is/was causing the problem.

     

    So while the newly installed driver seemed to work a bit better Outlook was still struggling. I happened to notice there was a newly recently released driver for windows 11 so I installed that and the problem I mentioned previously of full throttle download speeds but upload speeds basically non-existent resurfaced. As this cripples the entire computer, I again went through the removal of the driver and letting windows reinstall its preferred driver. After this the Outlook problems continued and I switched over to the Wi-Fi adapter so that Outlook would function normally.

     

    As all the problems just started I assume at this point it probably was triggered by some combination of Windows update combined with and Outlook version that, combined with my NIC driver, was causing problems. So I went through some old directories on my computer and found one of the original driver packages from Intel (from  2018) and installed that, thinking I had little to lose and that by going way back in the driver history I might get the OS, Outlook, and the NIC to play nicely together. So far it seems to be working! Outlook is working in Cached mode, I am able to send emails, and the download/upload speeds are great. I just hope it stays like this........

     

    So thanks again for your suggestions and advice. This may be a unique problem to just my computer setup but I hope by going way back in the NIC driver history I may have found a solution. I'll update this thread if things change.

     

    Paragon06