Since the last patch (v1.324), I experienced a problem that couldn't launch NF properly.
I always got stucked at the blackscreen right after the HS finished updating; the NavyFIELD.exe file seemed have no mood to run.
I tried to re-install the game or even formatted my PC
However, when I downloaded and installed the new version of NF, the problem seemed getting even worse.
This was what the game showed when I re-install everything

than I restarted the game and got several things downloaded, but when I came back to the log-in screen
it said Datafile has corrupted!!
I spent a lot of time searching for solutions. I'd got some advises from the forum here, but still didn't work.

But today I tried something new, and it worked!
Here is what I did, not so sure which step(s) made that happen, you could follow this see if you could get it fixed too:

Step 1) Go to Control Panel using Add/Remove uninstall NF(don't use NF's original Uninstaller)
Step 2) Go to C:\Program Files delete the complete folder of "SD EnterNET"
Step 3) Download NF old version(v1.319)(not sure if 1.320 will work too)
              https://navyfieldusa-sdenternet.ktics.co.kr/Download/NF1319.exe 
Step 4) Download Patch v1.323
              https://navyfieldusa-sdenternet.ktics.co.kr/Patch/Patch1323.exe
(those links are provide by BBR_InsUW) See: https://fm.en.navyfield.com/Community/Forum/View.aspx?category=E01&num=1862

Step 5) Install NF v1.319 but change the defult directory to somewhere else(NOT C:\Program Files\SD EnterNET\NavyFIELD) when installing
Step 6) Choose "finish" and don't run the game after installing
Step 7) Install the patch v1.323(don't try to install v1.324 Patch. You will get the same problem as you see on the screenshot above)
Step 8) After the patch finished installing, start NavyFIELD Launcher, and let it update to v1.324 there

When all the updates are completed, it should work properly, as it used to be:)