Convert FAT16 to FAT32 in Windows 98

This article explains how Microsoft Windows 98 handled the transition between file systems using its built-in Drive Converter tool. Upgrading from FAT16 to FAT32 allowed users to optimize hard drive storage capacity, eliminate partition size limits, and reduce wasted disk space without requiring a full drive reformat or data loss.

In Microsoft Windows 98, the dedicated tool used to convert drives from FAT16 to FAT32 was the Drive Converter (FAT32) wizard. The underlying executable for this utility was named CVT.EXE.

Users could access the Drive Converter through the graphical interface by navigating to:

Start > Programs > Accessories > System Tools > Drive Converter (FAT32)

Alternatively, it could be launched by typing cvt1.exe or cvt.exe into the Run dialog box.

Why the Conversion Was Necessary

The older FAT16 file system was limited to maximum partition sizes of 2 gigabytes (GB). As hard drives grew larger in the late 1990s, users with FAT16 had to divide single physical hard drives into multiple smaller drive letters (such as C:, D:, and E:). Additionally, FAT16 used large cluster sizes on larger partitions—often 32 kilobytes per cluster—which created significant "slack space" where small files occupied far more disk space than necessary.

FAT32 resolved these issues by supporting single partitions up to 2 terabytes and utilizing smaller 4-kilobyte cluster sizes, significantly increasing available storage efficiency.

How the Utility Worked

The Drive Converter guided the user through a step-by-step wizard:

  1. Drive Selection: The user selected the specific FAT16 drive volume to convert.
  2. Compatibility Warning: The utility warned the user that older operating systems, such as MS-DOS 6.22, Windows 95 (original retail release), and Windows NT 4.0, would no longer be able to read the converted drive.
  3. Backup Recommendation: The wizard prompted the user to back up critical files and automatically offered to run the Microsoft Backup utility.
  4. Antivirus and Disk Utility Check: The utility checked for incompatible disk tools or active antivirus programs that might interfere with disk structures.
  5. Conversion in MS-DOS Mode: To safely alter the file allocation tables, Windows 98 restarted the computer into MS-DOS mode, executed the conversion process, and then rebooted back into the Windows desktop environment.

Limitations of the Tool

The Drive Converter was strictly a one-way process. Once a partition was converted to FAT32, the native Windows 98 utility could not convert it back to FAT16; reverting required backing up data, repartitioning or reformatting the drive with FDISK and FORMAT, and restoring the files.