The 0xE000078B error code means OneNote is having trouble communicating with the webserver where your notebook is stored. Most likely, there’s been a server timeout, which occurs when the server is busy and can’t respond to your requests. Follow the below troubleshooting guide to Fix OneNote Error 0xe000078b (Server Timeout) in very simple steps.
A server connection timeout means that a server is taking too long to reply to a data request made from another device. Timeout errors can happen for several reasons. The server, the requesting device, the network hardware, and even an Internet connection can be at fault.
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Steps to Fix OneNote Error 0xe000078b (Server Timeout)
Check Whether There are Conflicts With Antivirus and Firewall
Check if your Antivirus program is blocking any of the programs that are getting install on your computer. It’s always suggested to disable your antivirus before you install any program on your computer.
Clear Temporary Files and Temporary Internet Files
There might be temporary files and temporary internet files and the junk files in your computer which will cause the registry issues and make some services not responsive. These temporary files might cause trouble for the system programs.
You need to optimize and tune up your computer.