With Office LTSC or 365 when opening files in Word, Excel, and PowerPoint from a network drive it can be very slow.

What I have found helps the most, to open files instantly without a long delay:

• Open each application – Excel, PowerPoint and Word
• From the File tab choose Options bottom left
• From the left hand side menu choose Trust Center
• Click Trust Center Settings… button
• Choose Trusted Locations from the left hand menu
• Check – Allow Trusted Locations on my network (not recommended) if it is not checked
• Click the Add new location… button
• Type in the drive letter z:\ or share name \\server\share\ and more in like check Subfolders of this location are also trusted as well, and click OK – update drive letter and server and share name to your needs
• Click OK, and OK again, and one last time click OK
• Try out accessing a file in that program, it should open much faster
• You need to do that for each program