Apt update fails at chrome stable main: "File has unexpected size (1103 != 1104). Mirror sync in progress?"

The several users who called it as being a repository server problem seem to have been right.

Even several hours after first seeing the error and after plenty of reboots the error wouldn't go away yesterday.

Today, however, the error is gone. I can now run apt update without any problems. Thanks everyone for saving me many hours of pointless debugging. :)

On Ubuntu 18.04 system you can list and remove PPA using Software & Updates application. Start Software & Updates application , navigate to Other Software tab and Remove or Edit any highlighted PPA repositories:

You can use the following commands.

sudo apt-get clean clears out the local repository of retrieved package files

sudo apt-get update downloads the package lists from the repositories and "updates" them to get information on the newest versions of packages and their dependencies.

sudo apt-get clean
sudo apt-get update