The issue occurs because of unsupported use of the registry. This update addresses a compatibility issue. You might receive the error, 'Document not saved.' For Microsoft Office apps, this issue only affects the 32-bit versions. If you use some commercial or enterprise security software that uses extended file attributes, this issue will likely affect you. You might have issues when you save, copy, or attach files. This update addresses a known issue that affects 32-bit apps that are large address aware and use the CopyFile API. This security update includes improvements that were a part of update KB5026446 (released May 24, 2023). When you install this KB:

I have found other threads online with simlar issues but none of them seem to offer a solution other than everything we have already tried.This update addresses security issues for your Windows operating system. Or could this be something to do with autodiscover failing to work on that particular account and device?Īny suggestions would be hugely appricated. Is it possible that something within the mailbox is causing this to happen? Should we empty the mailbox and archive all the mail? Now upon speaking with MS they seem to refuse to support us because we have a business account, and that we need to contact our technical support or partner? We have no technical support or partner and set up the outlook 365 account ourselves so it seems we are now stuck and may have to migrate to another service. So at this point I dont think it is the machine its-self as it has been completely reformatted with a new OS?. We replaced the hard drive in that machine and installed a fresh copy of Win 10, and a new licensed copy of office 2016 pro plus thinking that Win 8 may be the culprit. Initially the problem was occuring on Win 8.1 Office 2016. etc etc, but they are only temporary fixes and the problem returns anywhere within a few minuites to several days. checked quarantine and outgoing spam settings in the o365 exchange control panel.reformatting the laptop with windows 10,.The issue is limited to this particular laptop and account only. The same email account is also being used on other laptops a mac and an iphone which are NOT experiancing this issue. The machine has to be restarted and then they send immediatly upon opening outlook. Some emails send up until a point and then it randomly stops. This particular account has intermittent issues with sending and emails just sit in the outbox.

We have 10-15 office 365 exchange email accounts and they all work perfectly fine apart from one account on one device. Ok this is a weird one and its been ongoing for many months, wondering if anyone has any ideas.

Outlook mail stuck in outbox office 365