AppHangB1 error is an issue that may randomly pop up when users try to launch games on Steam or other apps. It is an incredibly annoying problem and reportedly, a number of users have faced this error. Because of this error, systems become very slow and unresponsive. If you would like to fix this error, then here are some solutions given below.

Turn off Antivirus Software

You should pursue the directions given below:

Firstly, find and click on the icon of the Windows Firewall at the lower right side of the taskbar.
Or else, insert the ‘windows firewall’ in the Windows Search and select the OK button.
Then select the section of ‘Turn Windows Firewall on or off’ situated at the left panel.
You will have to disable Windows Firewall on Public and Private settings.
Later, click on the OK button.
Now, reboot the Steam or the app that you have an issue with, then run it as administrator.
Configure Launch Settings on Steam

You should pursue the directions given below:

First of all, find the standard location of the Steam client by going to the C: drive and then choose Program files (x86)\Steam folder.
After that, you will be required to create a ‘steam.exe’ shortcut into a similar folder.
Go to the shortcut and right-click on it, then pick the Properties option.
You should reach the tab of the Shortcut of properties and find the Target section.
When you see ‘C: Program Files (x86)\SteamSteam.exe’, add ‘-dx9’ at the end.
Select the OK button.
You have to launch the Task Manager and end the task of Steam Client Bootstrapper.
Modify the Launch Settings of Game Individually

You should pursue the directions given below:

Navigate to Steam and launch it.
Then select the section of the Library wherever each of the games is kept.
Select the game and right-click on it to invoke the error, then select the Properties option through the list.
You should click on the tab of the General.
You can select the ‘Set Launch Options’ option.
You will see a box on your screen, insert ‘-dx9’ into it, and select the OK button.
Click on Apply, and then OK.
Later, you will be required to close Steam.
Using Safe Mode

You should pursue the directions given below:

Open the Run command prompt.
Thereafter, input ‘msconfig’ into it and tap the Enter button to launch the System Configuration Windows.
Then select the tab of Boot.
Go to the ‘Safe boot’ option and choose the Network option beneath it.
Click on Apply.
Later, reboot the system.
By following the stepwise solutions mentioned above, you can fix the Apphangb1 error on Steam.

source: https://geekswire.uk.com/how-to-fix-the-apphangb1-error-on-steam/