Uploads get stuck at 45%

At 45% of the upload process, Steam will actually start uploading files to the Steam servers. If you are trying to publish Wallpaper Engine content to the Steam Workshop and you are stuck at 45%, it means your Steam is unable to upload files to the Steam servers. Make sure that no firewall or antivirus application is blocking Steam from uploading files. Please also see the official guide on Steam network ports:

• Required Ports for Steam

This issue is always some sort of network issue, you will need to investigate what is blocking your Steam properly communicating with the Steam servers.

Also make sure that your router or a firewall is not blocking the IP address range of the Steam servers, make sure that direct IP connections are possible. Exclude the following IP address range from any block list: 208.64.200.0 - 208.64.203.255.

TIP

This network issue can also be caused by a firewall in your network router. Make sure that no network router is blocking Steam's upload. Try If uploads work through a mobile wi-fi hotspot - in that case your router is likely at fault and not any software on your computer.