XLSTAT: How to Fix "Run-time Error 1004 - Excel Cannot Access .xla File" on Windows

 

Issue

When you try to open XLSTAT or run an analysis in Microsoft Excel on Windows, you see this error:

"Run-time error '1004': Excel cannot access a .xla file"

or

"Run-time error '1004': Excel cannot access a .xlam file"

This error occurs when Excel cannot find or access the XLSTAT add-in files (.xla or .xlam files) it needs to run. There are two main causes for this error, depending on when it appears:

• If it happens right after opening XLSTAT: Your antivirus is blocking XLSTAT files

• If it happens when running an analysis: Either your antivirus is blocking files, OR you recently switched from 32-bit to 64-bit Office and the registry needs to be updated

Follow the appropriate section below based on when the error appears.

Case 1: Error Right After Opening XLSTAT

When this happens: You see the error immediately when you try to open XLSTAT in Excel, before running any analysis.

Cause: Your antivirus or security software is blocking XLSTAT files from being accessed.

Solution: Restore Blocked Files and Add XLSTAT to Antivirus Whitelist

Step 1: Release XLSTAT Files from Antivirus Quarantine

1. Open your antivirus program.

2. Look for a "Quarantine" or "Blocked Files" section (usually in Protection or History).

3. Search for XLSTAT files:

   • Look for any files with .xla or .xlam extension

   • Look for any files with "XLSTAT" in the name

4. If you find quarantined XLSTAT files:

   • Right-click on each file

   • Select "Restore", "Whitelist", or "Allow"

   • Confirm the action

5. Close your antivirus program.

Step 2: Add XLSTAT Installation Folder to Antivirus Whitelist

1. Open your antivirus program again.

2. Look for Settings, Protection, or Exclusions menu.

3. Find the option to add folders to the whitelist or exception list

4. Add your XLSTAT installation folder:

   • Default location: C:\Program Files\XLSTAT

   • Or: C:\Program Files (x86)\XLSTAT (on some systems)

5. If your antivirus does not allow adding entire folders, you must add each XLSTAT file individually:

   • Open File Explorer

   • Go to C:\Program Files\XLSTAT

   • Look for all files with .xla or .xlam extension

   • Add each file to your antivirus whitelist (this may take several minutes)

6. Save your antivirus settings and close the program

Step 3: Repair XLSTAT

1. Close Excel completely.

2. Right-click the Windows Start button (bottom left of your screen).

3. Select "Apps and Features" (or "Installed Programs").

4. Scroll down and find "XLSTAT" in the list.

5. Click on XLSTAT to select it.

6. Click the "Modify" button (or three dots menu > Modify).

7. A dialog box appears. Select "Repair" or "Quick Repair".

8. Click "Repair" and wait for the process to complete.

9. Restart your computer when prompted.

Step 4: Verify the Fix

10. Open Excel.

11. Open XLSTAT from the menu or ribbon.

12. Check if the error has disappeared

Case 2: Error When Running an XLSTAT Analysis

When this happens: XLSTAT opens without problems, but you see the error when you try to run an analysis.

Cause: Either your antivirus is blocking files (see Case 1 above), OR you recently switched from 32-bit Office to 64-bit Office and the Windows registry needs to be updated.

 

First, Try Case 1 Solutions

Before proceeding below, follow all steps in Case 1 (Quarantine Release, Antivirus Whitelist, and Repair XLSTAT). Many analysis errors are also caused by antivirus blocking.

If the error persists after completing Case 1, proceed to the registry fix below.

 

If Error Persists: Update Windows Registry After Office Version Change

Important: This solution applies only if you recently changed from 32-bit to 64-bit Microsoft Office (or vice versa).

Warning: Editing the Windows Registry can affect your computer if done incorrectly. Follow these steps carefully. If you are not comfortable editing the registry, contact XLSTAT Support for assistance.

Step 1: Open the Registry Editor

1. Press the Windows key + R on your keyboard.

2. A small dialog box appears. Type: REGEDIT

3. Press Enter or click OK.

4. The Registry Editor window opens. (If prompted by User Account Control, click Yes).

Step 2: Find the REFEDIT.DLL Key

5. In the Registry Editor, press Ctrl + F to open the Find dialog.

6. Type: REFEDIT.DLL (in capital letters).

7. Click "Find Next" or press Enter.

8. Wait for the Registry Editor to search (this may take a few seconds).

9. When found, the Registry Editor highlights the REFEDIT.DLL key.

10. Look at the current path shown in the (Default) value. It should display a file path, for example:

    • C:\Program Files (x86)\Microsoft Office\... (32-bit path - this is the problem if you switched to 64-bit)

    • C:\Program Files\Microsoft Office\... (64-bit path - this is correct)

Step 3: Locate the Correct REFEDIT.DLL File

11. Open File Explorer (Windows key + E).

12. Navigate to: C:\Program Files\Microsoft Office

13. In the search box (top right of File Explorer), type: refedit.dll

14. Press Enter to search.

15. Wait for the search to complete. You should see the REFEDIT.DLL file listed.

16. Right-click on the REFEDIT.DLL file that appears in the search results.

17. Select "Open file location" to see the full path.

18. Look at the address bar at the top of the File Explorer window. This shows the full path, for example:

    • C:\Program Files\Microsoft Office\Root\Office16\REFEDIT.DLL

19. Click the address bar and press Ctrl + C to copy the entire path.

Step 4: Update the Registry with the Correct Path

20. Go back to the Registry Editor window (it should still be open from Step 2).

21. Look at the REFEDIT.DLL key that was found.

22. Right-click on the (Default) entry under REFEDIT.DLL.

23. Select "Modify..." from the menu.

24. A dialog box appears showing the current value (the old 32-bit path).

25. Select all the text in the Value Data field (press Ctrl + A).

26. Delete all the text (press Delete).

27. Paste the new path you copied earlier (press Ctrl + V).

    • Example: C:\Program Files\Microsoft Office\Root\Office16\REFEDIT.DLL

28. Click OK to save the change.

29. Close the Registry Editor.

30. Restart your computer.

Step 5: Verify the Fix

31. Open Excel.

32. Run an XLSTAT analysis to confirm the error is gone.

After Completing These Steps

1. Test XLSTAT thoroughly:

   • Open Excel

   • Run a simple XLSTAT analysis

   • Confirm it completes without errors

2. If the analysis runs successfully, the error has been fixed.