Even if you delete a chat from Microsoft Teams, it can be restored, the Ministry of Internal Affairs and Communications' explanation is questionable

I can't check it because it has been deleted. The Ministry of Internal Affairs and Communications has provided this explanation regarding the controversial Microsoft Teams chat. He says he doesn't know when it was deleted or who deleted it.

Meanwhile, Minister of Internal Affairs and Communications Hayashi said on the 4th that the deleted chats were ``used for internal business communications, so there is no need to confirm by any means such as restoration.''

Is there a way to check in the first place?

According to Microsoft's official documentation, even if you delete a chat, there are permissions and mechanisms that allow you to view posted content under certain conditions. Asahi Shimbun engineers conducted an actual test and confirmed that even operations to delete a chat leave a related record showing who did it and when.

Teams chat is included in Microsoft 365, a business cloud service provided by Microsoft for government agencies and businesses.

According to Microsoft, Teams chat has a mechanism that saves records in addition to the screen that users usually see, so that government agencies and companies using the service can search them when conducting internal investigations. If the storage conditions are met, even if the chat itself has been deleted, it can be searched by time or keyword, and the title, author, content, and date and time can also be checked.

Dedicated permissions are required to check these details, and in many cases this can be accessed by a limited number of people within an organization who have been given permission to carry out internal investigations.

Verification “who operated and when” is also recorded.

User operations are also recorded as an "audit log." System administrators and investigators who are authorized to examine audit logs can search and retrieve stored records to see which users performed what operations and when. This is different from the permission to check the content posted in the chat.

Asahi Shimbun reporters worked with engineers to examine how Teams chat works.

Let's explore with an engineer

In fact, a group chat with multiple people...