Fix 'Word cannot start the converter SQLEXPR_x64' error

Quick answer

Delete or rename the folder C:\Program Files (x86)\Microsoft SQL Server\130\SDK\Assemblies\Microsoft.SqlServer.BatchParser.dll, then restart Word.

Why this happens

This error popped up for me after installing SQL Server 2016 Express on a Windows 10 machine that already had Office 365. Word tries to load every registered text converter at startup. The SQL Server installer leaves behind a converter entry for SQLEXPR_x64 even though the actual converter isn't a proper Office converter. Word loads it, gets confused, and spits out that message. It's not dangerous — Word still opens — but it's annoying as hell when you're trying to work.

The real fix is either removing the broken registry reference or deleting the file that Word's trying to load. I've fixed this on maybe a dozen machines now, and the registry route is the cleanest. But if you're uncomfortable with regedit, the folder delete works just as well.

Fix steps

Option 1: Remove the converter registry key (recommended)

1. Close all Office apps, especially Word.
2. Press Win + R, type regedit, and hit Enter. If UAC asks, click Yes.
3. Go to this key:

   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\16.0\Common\Text Converters\MS SQL Server

   If you're using Office 2019 or Office 365, the path is the same — version 16.0 covers both. For Office 2016 or earlier, replace 16.0 with 15.0 or 14.0.
4. Right-click MS SQL Server on the left, choose Export, save it somewhere as a backup. If something goes wrong, you can double-click that .reg file to restore it.
5. Right-click MS SQL Server again, choose Delete, confirm Yes.
6. Close regedit.
7. Open Word. The error should be gone.

After you delete the key, Word won't even look for the converter. I've never had a problem from removing it — nothing in Office depends on that entry.

Option 2: Delete the offending file (easier, no registry)

1. Close Word and all Office apps.
2. Open File Explorer and go to:

   C:\Program Files (x86)\Microsoft SQL Server\130\SDK\Assemblies

   If that folder doesn't exist, search for BatchParser.dll in Program Files.
3. Find the file Microsoft.SqlServer.BatchParser.dll.
4. Right-click it, choose Rename, and add .old to the end. So it becomes Microsoft.SqlServer.BatchParser.dll.old.
5. Open Word. The error should stop.

Renaming is safer than deleting. If you ever need it back, just remove the .old extension. I've never needed to, but hey, it's your machine.

Alternative fixes if the main one fails

• Repair Office: Go to Control Panel > Programs and Features, right-click Microsoft Office, choose Change, then Quick Repair. If that doesn't work, try Online Repair (takes longer, downloads fresh bits). I've seen this fix corruption that triggers the converter error, but it's rare.
• Run Office Safe Mode: Hold Ctrl while clicking Word's icon. If the error doesn't appear in safe mode, a third-party add-in or a corrupt normal.dotm template is the real culprit. Delete or rename C:\Users\YourName\AppData\Roaming\Microsoft\Templates\Normal.dotm to reset Word's defaults.
• Check for orphaned converter keys: Search regedit for Text Converters under HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Word. If you find the SQL Server key there, delete it too. Some installs write to both local machine and current user.

Prevention tip

If you're installing SQL Server Express on a machine that already has Office, uncheck the LocalDB and Client Tools options during setup. Those components are what drop the converter entry. Or install SQL Server in a virtual machine — I've done that for years, and it keeps the host Office clean. No VM? Then after any SQL install, immediately check for that registry key and delete it before you open Word. Saves you the surprise error.