How to Quickly Resolve VBA Error 400 in 3 Minutes (Excel)

Written by Kasper Langmann

VBA Error 400 is a common issue that Excel users encounter when working with macros. This error can be quite frustrating, especially when you’re in the middle of an important task. However, the good news is that it can be resolved quickly and easily. In this guide, we will walk you through the steps to fix this error in just three minutes.

Understanding VBA Error 400

The first step towards resolving any problem is understanding it. VBA Error 400, also known as “Form Already Displayed; Can’t Show Modally” error, typically occurs when there’s a conflict with the modal property of a user form. This error can also be triggered if a macro is trying to execute a command that Excel cannot perform.

It’s important to note that VBA Error 400 is a runtime error, which means it only appears when a specific macro is run. It does not prevent Excel from launching or functioning normally outside of the problematic macro.

Common Causes of VBA Error 400

There are several reasons why you might encounter VBA Error 400. One of the most common causes is a conflict with the modal property of a user form. If a user form is set to modal, it means that the user must close the form before they can return to the worksheet. If a macro tries to display a modal form while another modal form is already open, it can trigger VBA Error 400.

Another common cause of this error is a macro trying to perform an action that Excel cannot execute. For example, if a macro tries to delete a protected worksheet, it will trigger VBA Error 400.

How to Resolve VBA Error 400

Now that we understand what VBA Error 400 is and what causes it, let’s dive into how to resolve it. The process involves three steps: identifying the problematic macro, understanding the error, and finally, fixing the error.

Step 1: Identifying the Problematic Macro

The first step in resolving VBA Error 400 is to identify the macro that is causing the error. To do this, you will need to use the Debug feature in VBA. When the error message appears, click on “Debug”. This will highlight the line of code that is causing the error.

Once you’ve identified the problematic macro, it’s a good idea to make a backup of it. This way, you can revert to the original code if something goes wrong while you’re trying to fix the error.

Step 2: Understanding the Error

Once you’ve identified the problematic macro, the next step is to understand why it’s causing VBA Error 400. This requires a bit of detective work. Look at the highlighted line of code and try to understand what it’s trying to do. Is it trying to display a modal form? Is it trying to perform an action that Excel cannot execute?

If you’re not sure what the code is trying to do, it can be helpful to use the VBA Help feature. You can access this by clicking on “Help” in the VBA toolbar. This will provide you with more information about the highlighted line of code and what it’s supposed to do.

Step 3: Fixing the Error

Once you’ve identified the problematic macro and understood why it’s causing the error, the final step is to fix the error. This will involve modifying the problematic line of code.

If the error is being caused by a conflict with the modal property of a user form, you will need to change the modal property of the form. You can do this by going to the properties window of the form and changing the “ShowModal” property to “False”.

If the error is being caused by a macro trying to perform an action that Excel cannot execute, you will need to modify the macro so that it no longer tries to perform this action. This might involve removing the problematic line of code or replacing it with a different command.

Preventing VBA Error 400 in the Future

Now that you know how to resolve VBA Error 400, let’s look at how you can prevent it from occurring in the future. The key to preventing this error is to write clean, efficient macros that do not conflict with Excel’s functionality.

Use Error Handling

One of the best ways to prevent VBA Error 400 is to use error handling in your macros. Error handling is a programming technique that allows you to anticipate potential errors and handle them gracefully. This can prevent your macros from crashing and causing errors like VBA Error 400.

Test Your Macros Regularly

Another important step in preventing VBA Error 400 is to test your macros regularly. This can help you catch potential errors before they become a problem. If you notice that a macro is causing an error, you can debug it and fix the issue before it affects your work.

Keep Your Macros Simple

Finally, try to keep your macros as simple as possible. The more complex a macro is, the more likely it is to cause errors. If a macro is becoming too complex, consider breaking it up into smaller, more manageable macros.

In conclusion, while VBA Error 400 can be a nuisance, it’s a problem that can be quickly and easily resolved. By understanding the error, identifying the problematic macro, and fixing the issue, you can get back to your work in no time. And by following the preventative measures outlined above, you can avoid encountering this error in the future.