Why the SQL Server Import Wizard Fails

The Driver Problem

The most common failure point is the OLE DB driver that connects SQL Server to Excel files.

Modern Excel files (.xlsx) require the Microsoft ACE OLE DB provider. Older files (.xls) can use the Jet provider. The wizard needs the right driver installed, and that driver must match your system architecture.

Here's where it gets messy:

• 64-bit SQL Server needs 64-bit drivers
• 32-bit Office installs 32-bit drivers
• You can't have both 32-bit and 64-bit ACE drivers installed simultaneously

If you have 64-bit SQL Server and 32-bit Office (common in many organizations), the wizard simply won't find a compatible driver. You get an error like “The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine.”

The Data Type Guessing Problem

Even when the driver works, the wizard has another major flaw: it guesses column data types by sampling the first few rows of your data.

If your first 8 rows contain numbers like “123” and row 9 contains “N/A”, the wizard types the column as numeric and then fails when it hits the text.

This is especially problematic with:

• Mixed data columns — IDs that are sometimes numeric, sometimes alphanumeric
• Sparse data — columns with lots of blanks followed by text
• Date columns — dates that Excel stores as numbers but should import as dates

You can increase the sample size through registry settings, but it's a hack, and sampling will never be as reliable as explicit type definitions.

The Truncation Problem

Another common failure: text truncation. The wizard determines column width from sampled data. If your first 50 rows have 10-character values but row 51 has a 500-character value, the import fails or silently truncates.

The error message, when you get one, says something like “Text was truncated or one or more characters had no match in the target code page.” Not exactly helpful in identifying which column or row caused the problem.

The Date Nightmare

Dates deserve special mention because they fail in uniquely frustrating ways.

Excel stores dates as serial numbers (days since 1/1/1900). When the wizard reads these, it might interpret them as:

• Actual dates (correct)
• Numbers (wrong — you get 45000 instead of a date)
• Text (wrong — you get “45000” as a string)

The outcome depends on cell formatting in Excel, driver behavior, and sometimes seemingly random factors. The same file might import differently on different machines.

Workarounds That Sometimes Help

If you're stuck with the wizard, here are some things that can improve your odds:

Match your architectures. Install 64-bit Office if you have 64-bit SQL Server, or use the 32-bit version of the wizard (dtswizard.exe from the 32-bit tools folder).

Format your Excel data explicitly. Before importing, format columns as Text in Excel to prevent type guessing issues. Yes, you'll need to convert types in SQL afterward, but at least the data gets in.

Add header rows with representative data. Put sample values in row 2 that represent the worst-case (longest text, mixed types) so the wizard samples them.

Use the “Edit Mappings” dialog. The wizard lets you manually set destination column types. Change everything to VARCHAR(MAX) or NVARCHAR(MAX) to avoid truncation, then clean up types after import.

When to Give Up on the Wizard

Honestly? The wizard is fine for simple, clean data with consistent types. If you're importing a small table with well-formatted data and matching architectures, it works.

But for real-world Excel files — the messy ones with mixed data, long text fields, inconsistent formatting, and the occasional formula error — the wizard creates more problems than it solves.

At some point, you spend more time working around the wizard's limitations than you would using an alternative approach.

Official Resources

• Import or export text files — Excel import basics
• Download SQL Server Management Studio — SQL Server tools