Before using the Partition Assistant, you’d better to remove the paging file in order to make the operation successfully.
Step 1. Right-click "This PC" and select "Properties" ->"Advanced system settings".
In the pop-up window, click "Settings..." under "Performance".
Step 2. In next window, choose "Advanced" and then click "Change..."
Step 3. Then it will pop up the setting window of the paging file, select D drive first, then select "No paging file" and click "Set".
After click "OK" the system will ask for rebooting. Then you could use the Partition Assistant to resize the partition. After resizing the partition you could reset the "Paging file".