Would you like a step-by-step guide on how to manually unblock legacy file formats in the Windows Registry for Office 365?
Navigate to C:\Program Files (x86)\Common Files\microsoft shared\TextConv .
Finding these converters today can be tricky, as Microsoft officially retired many of its "legacy" filters in the mid-2000s for security reasons. However, there are still three reliable ways to get the job done: 1. The Native Office File Converters (Old Versions)
You may need to add a "FileOpenBlock" exception in the Windows Registry to allow Word to recognize the older format.