$ilding Blocks.dotx cannot be found.
Any/all/some/most functions in Word/Excel/PP result in an error dialogue stating Building Blocks/the temp file, $ilding Blocks.dotx template cannot be found or is corrupted.
First Fix.
Save any open documents, close Word, and any open O365 applications, e.g. excel, outlook, and PowerPoint.
Navigate to: C:\Users\yourauid\AppData\Roaming\Microsoft\Document Building Blocks\1033\16 in windows explorer (replace yourauid with your Windows username).
For older or newer editions of office, there may be another folder inside " Document building blocks", 1032, 1031, 97 etc
There are (usually) two files and (usually) two temp files in that folder.
4 files total; it can be 3 2 or 1, though.
Create a new folder, Backup or BKUP and move/cut and paste any existing files into the new folder.
Depending on the office edition, the backup folder may need to be moved for this to work. Moving up a level/folder into 1033 etc should be fine.
Leave the file explorer window open so you can check the files get recreated once you run word etc. . Close the window once they do.
Re-open Word. All functions should be working and no documents should have been affected.