Hello, if you just bought this game and it isn't working you're probably frustrated.
Don't ask for a refund yet! This problem is fixable. I thought it was hopeless after browsing the internet for a day.. It isn't. Just follow my steps closely and try everything until it finally worked. Let's start!

Reinstall your game
This speaks for itself but I'll explain.
Note: You probably already tried this.

Step 1: Go to your Library
Step 2: Right-click Geometry Dash
Step 3: Click "Remove local content"

I hope it worked! If not, continue to the next fix.
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Delete your savegame
It could be that your save is broken.
I always recommend making an account and saving your data.
Note: Make a copy of your save for if this didn't work

Step 1: Press Windows + R
Step 2: Type "AppData" and press Enter
Step 3: Go to "Local"
Step 4: Go to "GeometryDash"
Step 5: Delete "CCGameManager.dat" and "CCGameManager.dat.bak"

I hope it worked! If not, continue to the next fix.
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Update your graphics card
Alright, this can be kind of hard to do.
There are three main drivers; Intel, NVIDIA and AMD.
I'll explain what the basics steps are. You can also google them.
Note: Make sure you download the correct driver

Step 1: Go to your graphics card manufacturers website
Step 2: Download the correct driver for your graphics card
Step 3: Follow the instructions

I hope it worked! If not, continue to the next fix.
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Wrong hardware settings for your monitor
Windows likes to change settings while using your computer.
You've got to refresh your hardware settings for your monitor. I'll tell how.
Note: Follow this closely. This works for most people!

Step 1: Press Windows + R
Step 2: Type "Control Panel" and press Enter
Step 3: Go to System and Security
Step 4: Find the "Administrative Tools" link
Step 5: Open "Device Manager"
Step 6: Go to "Monitors" and extend the menu
Step 7: Right click the monitor in the menu (most of the time called Generic PnP Monitor)
Step 8: Click "Uninstall"
Step 9: Click "Refresh Hardware Changes" in the toolbar menu above

I hope it worked! If not, continue to the next fix.
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C++ isn't updated or installed
Geometry Dash runs on the programming language C++
Microsoft doesn't update it for you so here are the steps on how to do it.
Note: If it says it's already configured you have to uninstall it

Step 1: Go to your Library
Step 2: Right-click "Geometry Dash"
Step 3: Click "Properties"
Step 4: Go to "Local Files" and then "Browse Local Files"
Step 5: Go to "_CommonRedist" and then "vcredist"
Step 6: Start both the setups and follow the instructions

I hope it worked! If not, continue to the next fix.
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Change compatibility mode
There are a lot of different Windows versions. You can run executables in an earlier Windows version than you own.
Note: Switch between different versions to see if one works

Step 1: Go to your Library
Step 2: Right-click "Geometry Dash"
Step 3: Click "Properties"
Step 4: Go to "Local Files" and then "Browse Local Files"
Step 5: Right-click "GeometryDash.exe"
Step 6: Go to "Properties"
Step 7: Go to "Compatibility"
Step 8: Check "Run this program in compatibility mode for:"
Step 9: Select "Windows 95"

I hope it worked! If not, continue to the next fix.
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Invisibly Running
It could be that your game is running but you can't see it.
You will have to manually close it and restart.
Note: The program is called Task Manager

Step 1: Windows + R
Step 2: Type "taskmgr"
Step 3: Search for "GeometryDash.exe" and close it
Step 4: Restart your game via Steam

I hope it worked! If not, continue to the next fix.
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Unreadable Library
This sounds quite weird. This game uses a library (DLL) called "libcocos2d".
The file might be corrupt in your system and that makes it unreadable.
Just follow these steps closely, don't do this wrong.
Note: Make sure to download the latest version

Step 1: Navigate to https://www.opendll.com/
Step 2: Type "libcocos2d"
Step 3: Download "libcocos2d.dll"
Step 4: Go to "My Computer"
Step 5: Go to your Library
Step 6: Right-click "Geometry Dash"
Step 7: Click "Properties"
Step 8: Go to "Local Files" and then "Browse Local Files"
Step 9: Drag "libcocos2d.dll" into the folder

I hope it worked! If not, continue to the next fix.
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Discord's In-Game Overlay
Some people have reported that Discord's In-Game Overlay causes the game to crash.
Disabling it for Geometry Dash could fix the issue.
Note: If you don't have Discord you can skip this step

Step 1: Open Discord
Step 2: Go to "User Settings"
Step 3: Go to "Registered Games"
Step 4: Look for "Geometry Dash"
Step 5: Click "Toggle Overlay" to turn it off

I hope it worked! If not, continue to the last fix.
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Big Picture Mode
If it still doesn't work, you could try opening the game in Big Picture Mode.
Note: The Steam UI could have changed after this guide was written

Step 1: Open your Steam client
Step 2: Click the "Big Picture" button featured in the top right corner in the Steam client
Step 3: Run Geometry Dash

I hope it worked! If not, you should get a new computer.

Hey, if it worked. Can you give it a like so others with the same problem can find it? Thanks!
If it still didn't work. There is something wrong with your system, you could ask for a refund or just
get a completely brand new computer or try to downgrade to Windows 7.

If you fixed your problem but it isn't in this list feel free to tell me and I will add it!