Before using Partition Assistant we highly recommend you do a complete defragment on the partition which you want to resize. The built-in defragment tool could assist you achieve this goal. Here are two methods of "How to defragment partition in Windows OS".
Method 1: Use the Properties of Your Local Disk
- Open My Computer.
- Right-click the local disk volume that you want to defragment, and then click Properties.
- On the Tools tab, click Defragment Now.
- Click Defragment.
Method 2: Use Computer Management MMC
- Start Computer Management MMC (Compmgmt.msc).
- Click Disk Defragmenter.
- Click the volume that you want to defragment, and then click Defragment.