If you can't change your default PDF opener to Adobe Acrobat, follow these steps:
1. Open Task Manager (CTRL+SHIFT+ESC), then click on the Details section.
2. Scroll down to msedge.exe (there will be many of them), and Right click on each one and click End Task, then click End process.
4. Go to any PDF file and Right click > Properties.
5. Click the Change button > Google Chrome > Set default
6. Then click the
Apply button.
7. Then repeat steps 4-6, but this time choose Adobe Acrobat as the default.