An embarrassing programming error caused Microsoft to have a less good start to the new year. E-mails going through the company’s Exchange servers are not arriving. Exchange is used for business, school, and university accounts. The reason for this is a bug that arose through the new year 2022.
Microsoft brings updates for its “MS Filtering Engine” at regular intervals. It filters malware and therefore needs to be updated frequently. This is saved with a ten-digit version number on the Exchange server with a variable of the type “Int32”.
Version number with too high a value
Since the version number starts with the current date, the latest version is called “2.201.010.001” – and this is exactly where the problem lies. The maximum size of Int32 variables is 2,147,483,647. The new file name caused an error because the value was higher. E-mails therefore get stuck in the filter system.
Exchange customers who host their e-mail servers themselves are affected; those who use Outlook 365 seem to be spared. Companies that use hybrid solutions are also affected. Your e-mails are routed through several third-party filters via “Centralized Mail Transport” and therefore receive errors even if they use the Microsoft cloud, explains system administrator Joseph Roosen on Twitter.
System administrators would therefore have to act quickly, even if the IT departments everywhere are likely to be understaffed due to the New Year. Even the fact that your own server is affected could not be noticed until late, as very few would expect e-mails on the weekend or on January 1st.
Microsoft is already working at full speed on a solution to the problem, as the company reports in its own tech community forum. It will take a few days before the patch can be deployed. The only workaround currently is to switch off the antivirus scanner – but only if additional software is active to protect against malware.