Unable to open File hyperlinks from Outlook

[DarylCheong]

I am unable to open file links from network shares in outlook. When the file link is clicked, there is no response.  These applies to all file links and folder links from network locations (Windows server shares) . We have various remote offices from Vietnam, Malaysia and Indonesia and the issue is happening to more and more users.

However, 

1) Attachments are able to open.
2) Web hyperlinks are able to open.

It only happened 2 days ago.

[#2]

We have the same problem. Last week it worked and this week it doesn't.

[#3]

Yes, same problem here.

[#4]

Just found on Bleeping Computer.

Security Update to O365 in July. Malware authors were able to misuse the opening of file hyperlinks, so it is blocked in Outlook as standard.

By going through the Internet Options in Windows, it is possible to add the local domains, where company files are stored to the Trusted Sites list. Once the file servers are in the trusted list, the hyperlinks will work again.

[#5]

In the heavily managed enterprise environment I work in, we still don't have a problem with web hyperlinks but we also are no longer able to open file links. Both full UNC paths to filenames and mapped drive paths stopped working a while ago. This is extremely inconvenient.

Some of the possibly paranoid talk about the behavior I've heard is suggesting that it is By Design, aimed at 'encouraging' everyone to start using links to SharePoint folders created via Teams, which do still work for us. When I'm feeling a bit cynical, that notion makes sense to me. After all, being able to understand and follow a deep folder structure is so 20th century...