How to Solve Format 4.0 Buffalo External Hard Drive Trouble, Help Me!

I'm attempting to format a 4.0TB Buffalo drive. But just a portion of it will let me format it; the other unallocated portion appears to be locked or trapped in some way. The choices are all grayed out. Any suggestions?

If you can't use the rest part of your Buffalo external hard drive, it may be caused by the partition scheme: GUID Partition Table (GPT) and Master Boot Record (MBR).

• MBR only supports a 2TB hard drive, limited to four primary or three primary and extended partitions.
• GPT has no size limit. It can support up to 128 primary and unlimited logical partitions.

Extended Reading: MBR VS GPT | What's the Difference and Which Is Better

In the MBR, Windows can only handle the first 2TB of the drive. The rest of the capacity will not be available. So you can't do a full format of Buffalo external hard drive. In contrast, GPT can see any hard drive that exceeds the capacity. You need to convert MBR to GPT first and then format it.

Diskpart or Disk Management requires deleting the existing partition first, which can cause data loss. So why not try a simple and safe conversion tool? EaseUS Partition Master is the most considerate choice for computer novices.

It simplifies all the procedures of converting MBR to GPT. You can easily solve format 4.0 Buffalo External Hard Drive problems in three simple steps.

Step 1. Launch EaseUS Partition Master and go to "Disk Converter."

Step 2. Select "Convert MBR to GPT" and click "Next."

Step 3. Select the target MBR disk and click "Convert."

After the conversion is complete, you can continue to use the tool to format your hard drive. EaseUS Partition Master provides a full service for your hard drive management.