Symptom: Program not updating when changes are being made and saved.

Quick Fix: MAKE SURE YOU DON'T ALREADY HAVE AN INSTANCE OF THE PROGRAM RUNNING!

What the error means:

When you try to build (compile) your program, the linker needs to create or update a file (usually an .exe file). But it can't write to the file because something else is using it or you don't have permission.

Common reasons:

• The program you're building is still running (you forgot to close it).

• Antivirus is checking the file and "holding" it.

• Search indexing (Windows searching) is using the file.

• File Explorer is somehow keeping the file open.

• You don't have permission to write in the folder.

How to fix it:

• Make sure the program you built is closed before building again.

• Restart your computer if something stuck.

• Tell your antivirus or Windows search to ignore your project folder.

• Make sure you have permission to write in the folder.