What is the QuickBooks Error 1638? A Complete Guide

Last Updated on February 12, 2026

The QuickBooks error 1638 is an installation error that you might run into while installing the QB Desktop application or installing its latest updates. If you get this error, you might already have QuickBooks installed. All you have to do is find your QuickBooks version and open it. However, if you haven’t installed the QB Desktop application yet, then it might be occurring due to program problems or the Firewall blocking your QB Desktop application. This can hamper your workflow and have a negative impact on your important accounting and bookkeeping processes. We will cover the potential causes of error 1638 in QuickBooks, along with the methods you need to troubleshoot it, in this blog.

Are you having trouble installing the QuickBooks Desktop application on your system? Feel free to contact our Accounting Helpline experts at 1.855.738.2784 today to resolve your problem at a moment’s notice!

Potential Causes of the QuickBooks Installation Error Code 1638

Listed below are the potential factors that can trigger the QuickBooks Desktop installation error code 1638 to appear on your screen:

1. You might already have QuickBooks installed.
2. A damaged Microsoft .NET Framework.
3. A damaged Microsoft MSXML.
4. Damaged Windows components can also cause this issue.
5. The Firewall is blocking the QB Desktop application.
6. Third-party apps are interfering with the QB Desktop installation process.
7. Missing installation files while installing the QB Desktop app.

These are the causes of the QuickBooks error code 1638.

Guided Methods to Resolve the QuickBooks Desktop Error Code 1638

Given below are the methods you can use to troubleshoot the QuickBooks installation error code 1638:

Find and Open QuickBooks

The reason you might not be able to install QuickBooks can be that the QB Desktop application is already installed. Hence, try to find and open the QB Desktop app with the steps given below:

1. Open the Start menu.
2. Find QuickBooks in the All Apps section.
3. Open the QB Desktop app.

If you can’t see it:

1. Open the Start menu.
2. Search for and open the Control Panel.
3. Hit OK.
4. Click on Uninstall a Program.
   
5. In the list of programs you see, select QuickBooks and open it.

If this doesn’t work, proceed to the next method.

Utilize the QB Install Diagnostic Tool

You can use the QB Install Diagnostic Tool from the QB Tool Hub to resolve the QuickBooks error 1638 with the steps given below:

1. Download and install the QuickBooks Tool Hub.
   
2. Open the QB Tool Hub app.
3. Navigate to the Installation Issues tab.
4. Click on the QuickBooks Install Diagnostic Tool.
   
5. Let the tool run.
6. It can take up to 20 minutes to finish working.

The installation error should now be fixed.

Register the MSXML DLL Files

You can register the MSXML DLL files to resolve the installation error code 1638 in QuickBooks Desktop with the steps given below:

For 64-Bit Operating Systems:

1. Open the Start menu.
2. Search for and open the Command Prompt:
   • Right-click and open the Command Prompt as an administrator.
3. Go to the C: prompt.
4. Type in cd\windows\syswow64.
5. Hit Enter.
6. Then, feed in regsvr32 MSXML6.dll.
7. Press Enter.

For 32-Bit Operating Systems

1. Open the Run menu:
   • Press Windows + R
2. Then, type cmd.
   
3. Hit Enter.
4. Now, type regsvr32 MSXML6.dll.
   
5. Press Enter.

Now, the QuickBooks error code 1638 should be patched.

Repair the MS NET Framework

A damaged Microsoft .NET Framework can prevent your QuickBooks Desktop app from installing or cause installation issues. You have to fix the NET Framework to resolve the QuickBooks installation error code 1638 with the steps given below:

1. Close all open programs.
2. Navigate to the Start menu.
3. Search for and open the Control Panel.
4. Click on Uninstall a Program:
   • Don’t worry, you don’t have to uninstall anything.
5. Select the Turn Windows features on or off option.
6. Find .NET Framework in the list.

Then, proceed to follow the steps based on which given scenario matches yours:

If the .NET Framework Checkbox Isn’t marked

1. Mark the checkbox to turn on the .NET Framework.
2. Press OK to save the changes.
3. Restart your PC.

If the .NET Framework Checkbox is marked

1. Select the checkbox again to turn off .NET Framework.
2. Don’t turn it on yet.
3. Hit OK to save the changes.
4. Restart your PC.
5. Then, turn on the .NET Framework again using the steps given above.

This would troubleshoot the QuickBooks error 1638.

Install the QB Desktop Application in Selective Startup Mode

Third-party apps running on your PC might be interfering with the installation procedure of QuickBooks Desktop. You have to install the QB Desktop app in selective startup mode to get rid of the QuickBooks error 1638 with the steps given below:

1. Hit Windows + R to open the Run menu.
2. Type in msconfig.
   
3. Press OK.
4. Navigate to the General tab.
5. Click on Selective startup.
6. Press the Load system services option.
   
7. Go to the Services tab.
8. Mark the Hide all Microsoft services checkbox.
   
9. Press Disable all.
10. Unmark the Hide all Microsoft services checkbox.
11. Choose Windows Installer from the list of services.
12. Hit OK.
13. Press Restart on the System Configuration window.
14. Install the QuickBooks Desktop app.
15. Open the Run menu again.
16. Type in msconfig.
17. Hit Enter.
18. Go to the General tab.
19. Click on Normal startup.
    
20. Press OK.
21. Press Restart on the System Configuration window.

The error should now be patched.

Make Firewall Exclusions for the QB Desktop App

If Windows Firewall is blocking the QB Desktop app, you may encounter QuickBooks error code 1638 while installing it. You can fix this by making Firewall exclusions for the QBDT application’s executable files, given in the table below, using the following steps:

Now, make exclusions for the QB Desktop application’s executable files given in the table above with the steps given below:

1. Open the Start menu.
2. Search for the Windows Firewall.
3. Open the Windows Firewall.
4. Select the Advanced Settings option.
   
5. Then, right-click on Inbound Rules:
   
   • You will have to create Outbound Rules after creating Inbound Rules.
6. Click on New Rule.
7. Select Program.
8. Press Next.
9. Proceed to click on This Program Path.
   
10. Now, choose Browse.
11. Locate and select one of the executable files given in the table above.
12. Hit Next.
13. Click on the Allow the Connection option.
14. Press Next.
15. Ensure all profiles are marked if you are prompted.
16. Hit Next.
17. Create a rule.
18. Name it something like QBFirewallException(name.exe).
19. Repeat the steps for each executable file given in the table above.

Now, just repeat the steps again to create Outbound Rules. Just right-click on Outbound Rules instead of Inbound Rules after you select Advanced Settings and follow the rest of the steps as they are.

Verify and Rebuild the Company File Data

If you are experiencing QuickBooks error 1638 while installing updates for the QB Desktop app, it may be due to a damaged company file. You can verify and rebuild your company file data to fix it with the steps given below:

1. Open the QB Desktop app.
2. Go to the File menu.
3. Click on Utilities.
4. Select Verify Data.
   
5. Now, navigate to the File menu again.
6. Select Utilities.
7. Click on the Rebuild Data option.
   
8. QB will ask to back up your company file before rebuilding your data.
9. Hit OK.
10. A backup is needed to rebuild your QB company file data.
11. Select where the backup would be saved.
12. Press OK.
13. Make sure not to replace an existing backup file.
14. Enter a unique name in the File name field.
15. Hit Save.
16. You will get the message stating that Rebuild has completed.
17. Hit OK.

Now, you should be able to update the QB Desktop app without any issues.

Use the Compatibility Troubleshooter

You can use the compatibility troubleshooter to resolve the QuickBooks error code 1638 with the steps given below:

1. Navigate to the location where you downloaded the QB installer.
2. Right-click on the installer.
3. Click on the Properties option.
4. Navigate to the Compatibility tab.
5. Select Run compatibility troubleshooter.
   
6. Click on Try recommended settings.

Now try installing the QB Desktop app again.

Use the Quick Fix My Program Tool

You can use the Quick Fix MY Program tool from the QB Tool Hub to resolve the QuickBooks error 1638 with the steps given below:

1. Open the QB Tool Hub application.
2. Navigate to the Program Problems tab.
3. Click on Quick Fix My Program.
   
4. Let the tool run.

You should now be able to install the QB Desktop application.

Use the QB File Doctor Tool

The QuickBooks File Doctor tool can be used from the QB Tool Hub application to resolve QuickBooks install error 1638 with the following steps:

1. Open the QB Tool Hub app.
2. Navigate to the Company File Issues tab.
3. Click on Run QuickBooks File Doctor.
   
4. It can take up to a minute to open:
   • If it doesn’t open, search for QuickBooks Desktop File Doc and open it manually.
5. Select your company file from the dropdown menu:
   • If you can’t see your file, select Browse and search to find your file.
6. Click on the Check your file option.
7. Press Continue.
8. Enter your QB admin password.
9. Hit Next.

Now, proceed to install the updates of the QB Desktop app.

Change the Permissions of the Temp Folder

Inadequate permissions of the temp folder can cause the QuickBooks installation error code 1638 to appear on your screen. You can fix this by changing the temp folder permissions using the steps given below:

1. Press Windows + R.
2. This would open the Run menu.
3. Type in %temp% in the Run menu.
   
4. Hit Enter.
5. The temp folder would open.
6. Right-click on the folder.
7. Select Properties.
8. Navigate to the Security tab.
9. Click on Edit.
10. Highlight your Windows username.
11. Mark the Full Control checkbox under the Allow column.
12. Hit OK twice.

Now, the problem should be resolved.

QuickBooks Error 1638 – A Quick View Table

In the table below is given a concise summary of this blog on the topic of the installation error code 1638 in QuickBooks Desktop:

Conclusion

The QuickBooks error 1638 is an installation error you might encounter while installing the QB Desktop application or its latest updates. If you get this error, you might already have QuickBooks installed. All you have to do is find your QuickBooks version and open it. However, if you haven’t installed the QB Desktop application yet, it might be occurring due to program issues or because the Firewall is blocking it. This can hamper your workflow and negatively impact your key accounting and bookkeeping processes. We have covered the potential factors that can trigger the 1638 error code to appear on your screen, along with the methods you need to troubleshoot it, in this blog.

If you are still unable to install the QuickBooks Desktop application, feel free to contact our Accounting Helpline experts at 1.855.738.2784 today, who can help resolve your problem at a moment’s notice!

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Edward Martin

Edward Martin is a Technical Content Writer for our leading Accounting firm. He has over 10 years of experience in QuickBooks and Xero. He has also worked with Sage, FreshBooks, and many other software platforms. Edward’s passion for clarity, accuracy, and innovation is evident in his writing. He is well versed in how to simplify complex technical concepts and turn them into easy-to-understand content for our readers.