Which stage of HDD partitioning delete the files?

I am planning to format my laptop. I have C and D. I want to completely delete drive C and make a partition of 200GB instead of 217GB. Then I want to take that leftover partition (17GB) and add it to D to have 250GB. On the D, I have my files and photos. I use C for OS and programs only. So if I take that leftover and merge it to D, will D get corrupted?

I would back up everything to an external drive. Then use the Partition Wizard ISO free version to work the partitions. Any non-destructive partition job has the chance of losing all your data. To do it without backup is a crap shoot.

If you are going to format Boot drive, you'll have to use some external boot device like Hireens' boot disk or from USB to do it from. Before you do that give disks and partitions a name so you don't mix them up. I have never lost any data using free version of Easus Partition Master from Hireens but it would be good idea to backup most important stuff first.

CountMike said:

If you are going to format Boot drive, you'll have to use some external boot device like Hireens' boot disk or from USB to do it from.

Click to expand...

The Partition Wizard ISO is a boot disc image. Just burn to CD and boot it.

The only 3rd party ,Backup software, partitioning which fully supports Windows 8/8.1, uEFI, GPT & Secure Boot.
Which is signed by Microsoft.

That I know of at this time is
Paragon 14, Out November 2013.
Hard Disk Manager Suite ? complete system management | PARAGON Software Group - disk partitioning, resize partition
Paragon Hard Disk Manager Professional - Overview