How to reduce the Pendrive size for legacy devices

SanDisk Cruzer Force 16 GB — Shrink to 8 GB FAT32 and Restore Full Capacity

1. Objective

This guide explains how to:

• Check the USB drive's identity, serial number, and capacity.
• Shrink a 16 GB USB partition to approximately 8 GB.
• Format the smaller partition as FAT32.
• Test compatibility with legacy devices.
• Restore the USB drive to one full-capacity partition.

Important: Formatting or deleting partitions erases data. Back up any files before starting.

2. Identify the SanDisk USB Drive

Open PowerShell as Administrator and run:

Get-CimInstance Win32_DiskDrive |

Where-Object {$_.InterfaceType -eq "USB"} |

Select-Object Model,Manufacturer,SerialNumber,Size,PNPDeviceID

Example output:

Model       : SanDisk Cruzer Force USB Device

Manufacturer : (Standard disk drives)

SerialNumber : 4C531001630416118384

Size        : 15998169600

PNPDeviceID : USBSTOR\DISK&VEN_SANDISK&PROD_CRUZER_FORCE&REV_1.00\4C531001630416118384&0

Check these fields to identify your drive:

• Model: SanDisk Cruzer Force
• Serial number: 4C531001630416118384
• Reported capacity: approximately 16 GB

The manufacturer field may show (Standard disk drives) in Windows; this alone does not indicate a counterfeit drive.

3. Check the Disk Number and Partition Style

Run:

Get-Disk |

Where-Object {$_.BusType -eq "USB"} |

Select-Object Number,FriendlyName,SerialNumber,Size,PartitionStyle,OperationalStatus,HealthStatus

Example:

Number           : 1

FriendlyName     : SanDisk Cruzer Force

SerialNumber     : 4C531001630416118384

Size             : 16005464064

PartitionStyle    : MBR

OperationalStatus : Online

HealthStatus      : Healthy

In this example, the USB drive is Disk 1.

Important: Your disk number might change after reconnecting the drive. Always verify the disk number and serial number before making changes.

4. Check the Existing Partition

Run:

Get-Partition -DiskNumber 1 |

Format-Table PartitionNumber,DriveLetter,Size,Type

Replace 1 with your verified disk number.

To check the volumes:

Get-Volume |

Format-Table DriveLetter,FileSystem,Size,SizeRemaining

Initially, your drive may have one partition of approximately 16 GB formatted as FAT32.

5. Format the Partition as NTFS

Windows Disk Management may not offer the Shrink Volume option for your current FAT32 partition.

To work around this:

1. Press Win + X.
2. Open Disk Management.
3. Identify the SanDisk USB drive by its capacity and disk number.
4. Back up your files.
5. Right-click its volume and select Format.
6. Select NTFS.
7. Complete the formatting process.

Formatting erases the files on the selected partition.

6. Shrink the NTFS Partition

1. In Disk Management, right-click the NTFS volume on the SanDisk.
2. Select Shrink Volume.
3. Wait for Windows to calculate the available shrink space.
4. Enter the amount of space to shrink in MB.
5. Click Shrink.

For an approximately 8 GB partition, shrink the volume by roughly 7,500–8,000 MB, adjusting for the actual size shown by Windows.

After shrinking, you should see:

• One smaller NTFS partition.
• Some unallocated space.

Leave the unallocated space unused for this experiment.

7. Format the Smaller Partition as FAT32

1. In Disk Management, locate the smaller partition on the SanDisk.
2. Verify its size and drive letter.
3. Right-click the partition and select Format.
4. Select FAT32 if available.
5. Complete the formatting process.

If FAT32 is unavailable, use a reputable partition-management utility that supports formatting an existing partition as FAT32.

Do not format the unallocated space or another disk.

8. Verify the Smaller FAT32 Partition

Check the filesystem and size:

Get-Volume -DriveLetter H |

Select-Object DriveLetter,FileSystem,Size,SizeRemaining

Replace H if the drive letter has changed.

Example output:

DriveLetter FileSystem      Size SizeRemaining

----------- ----------      ---- -------------

H          FAT32     8584675328   8584642560

This indicates:

• Drive letter: H:
• Filesystem: FAT32
• Volume size: approximately 8.58 billion bytes
• Available space: almost the entire partition

Check the disk and partition style:

Get-Partition -DriveLetter H | Get-Disk |

Select-Object Number,FriendlyName,SerialNumber,Size,PartitionStyle

Expected:

• FriendlyName: SanDisk Cruzer Force
• Physical capacity: approximately 16 GB
• PartitionStyle: MBR

9. Test on the Legacy Device

1. Safely eject the USB drive.
2. Connect it to the target legacy device.
3. Check whether the device recognizes the USB drive.
4. If it recognizes the drive, test reading files or booting, as applicable.

The physical USB drive still reports approximately 16 GB. Shrinking its partition only changes the partition size.

A legacy device may detect the smaller partition, report the full device capacity, or reject the drive because of other compatibility requirements.

MBR, FAT32, a single primary partition, or a specific cluster size may be required by some devices.

10. Restore the USB Drive to Full Capacity

Use this section when you want to undo the smaller partition and restore one partition across the available capacity of the USB drive.

Method A: Disk Management — Recommended

1. Back up all files on the SanDisk.
2. Open Disk Management.
3. Identify the SanDisk by its model and capacity.
4. Right-click the smaller FAT32 partition and select Delete Volume.
5. If there are other partitions on the SanDisk that you also want to remove, delete them only after verifying they belong to this USB drive.
6. Confirm that the desired capacity is now shown as unallocated.
7. Right-click the unallocated space and select New Simple Volume.
8. Choose the maximum available volume size.
9. Assign a drive letter.
10. Select FAT32 if available, or NTFS if preferred.
11. Finish the wizard.

The USB drive should now have one partition using nearly all of its capacity.

Method B: DiskPart — Rebuild the Partition Layout

Use this only if Disk Management cannot restore the desired layout.

WARNING: The clean command removes the partition information from the selected disk. Selecting the wrong disk can destroy access to data on another drive.

First, run this in PowerShell:

Get-Disk |

Where-Object {$_.BusType -eq "USB"} |

Select-Object Number,FriendlyName,SerialNumber,Size,PartitionStyle

Confirm the SanDisk model, serial number, and capacity.

Then open DiskPart:

diskpart

list disk

select disk 1

detail disk

Replace 1 with the verified disk number. Check detail disk carefully before proceeding.

Only after confirming that the selected disk is the SanDisk, run:

clean

convert mbr

create partition primary

format fs=fat32 quick

assign letter=H

exit

This creates one primary partition using the available capacity and formats it as FAT32.

If DiskPart refuses to format the volume as FAT32, use a reputable FAT32-capable formatting utility instead. Do not run clean again just to change the filesystem.

11. Verify the Restored Capacity

Check the physical disk:

Get-Disk |

Where-Object {$_.BusType -eq "USB"} |

Select-Object Number,FriendlyName,SerialNumber,Size,PartitionStyle

Check the volume:

Get-Volume -DriveLetter H |

Select-Object DriveLetter,FileSystem,Size,SizeRemaining

Expected result:

• Physical disk: approximately 16 GB.
• One partition: nearly the full available capacity.
• Filesystem: FAT32 or NTFS, depending on the selected format.
• Partition style: MBR.

Windows may display the volume as approximately 14.9 GiB because manufacturers and Windows use different capacity units.

12. Important Notes

• Shrinking a partition does not change the physical USB capacity reported by the controller.
• Formatting a partition changes its filesystem, not the hardware's reported capacity.
• This procedure does not prove whether a SanDisk drive is genuine.
• Back up data before formatting, shrinking, deleting, or rebuilding partitions.
• Always verify the disk number, serial number, and capacity before making changes.
• Legacy-device compatibility is not guaranteed by reducing the partition size alone.

Final result: You can experiment with an approximately 8 GB FAT32 partition on a 16 GB USB drive, test it on older hardware, and restore the drive to a single full-capacity partition when finished.