Windows 10: 4TB drive, a 16MB page file tells me that my C: drive is too small

Brand new win installation on a 4TB drive but even a setting virtual memory to 16MB warns me that my C: drive is too small.

:)

 

Page File

Set minimum and maximum to a constant number as suggested by others, that will help reduce fragmentation on the drive coz of different page file sizing.

 

Paging File

Diskeeper does this (it's not free also), or
disable page file, restart computer, delete C:\pagefile.sys, defragment drive C:, enable page file again.

 

GPT disk conversion for both data drives and C drive


Macrium Rescue disk can be used to convert from MBR to GPT and vice versa without doing a fresh install of Windows.

1. Download Rescue6.1.1081X64.iso - Google Drive and use Rufus to create a bootable USB disk. Skip this step if you've already created the Macrium Rescue disk.
2. Download: BootEFI_Only-00-00.zip - Google Drive . Unzip to an external or an internal HD
   NOTE: This is a copy of the first 3 partitions of my current Windows 10 x64 (450MB Recovery, 100MB EFI and 16MB MSR)
3. Boot up Macrium Rescue disk and create a backup of your current Windows to another internal/external HD. It serves 2 purposes: you'd have a backup of your current Windows in case things go wrong and then use it to restore the C drive on the next steps.
4. Next, switch the BIOS to UEFI and use Macrium to restore the first 3 partitions downloaded in step 2 to your current MBR Windows. No need to convert or Format, Macrium will do it.
5. Again with Macrium, select the backup image from step 3, and copy back the C drive after the 3 partitions.
   After this step, you should have: 450MB, 100MB, 16MB and C drive (GPT partition scheme)
6. From Macrium, click on Fix the Windows Boot Problems
7. Reboot. Your Windows should be in UEFI mode.