Thanks for posting here in the Community, @luckytiger1997. 

It could be the data in your Mac Air company file is damaged. This might be the reason the system does nothing when you delete an account. 

To help fix this, let’s first make sure your QuickBooks Desktop for Mac is updated. This improves the program functionality and fix known issues with the software. 

Second, let's open a sample company file to isolate the issue. This way, we can determine if this is specific to program or with the file. Here’s how: 

1. Close your QuickBooks.
2. Open it back.
3. Choose Open a sample file in the No Company Open window.

Once the sample file opened, go back to the Chart of Accounts menu. Then, highlight the account so you can delete it. If it works, let’s run the verify and rebuild utilities within the affected company file. The Verify Data utility identifies all the errors. The Rebuild Data utility fixes these errors. 

To run the first utility: 

1. Go to File at the top menu. 
2. Select Utilities.
3. Choose Verify Data.
4. If you see QuickBooks detected no problem with your data, choose OK. 

To run the second utility: 

1. Go to File at the top menu. 
2. Select Utilities.
3. Choose Rebuild Data.
4. On the QuickBooks Information window, select OK.
5. Click OK when you see the message, “Rebuild has completed”.

For detailed steps, go through this article: Resolve Data Damage On Your Company File. 

You can visit this PDF article: QuickBooks Desktop for Mac User's Guide. You can effectively manage your accounts by going to Chapter 3 in this guide. Also, this lets you learn more about the features of the Mac version. 

Just leave a reply below if you need further assistance. I'll gladly help, @luckytiger1997.