I downloaded the latest version of SQL Developer (4.1.2) to a just-provisioned, pristine server running Windows Server 2012 R2.
I downloaded sqldeveloper-220.127.116.11.64-x64.zip, unzipped it, and placed it under c:\program files\sqldeveloper-18.104.22.168.64-x64\. I double-clicked the main sqldeveloper executable and expected it to "just work" (as it usually does), but this time it didn't.
I got the following error message:
sqldeveloper64W.exe - System Error
The program can't start because MSVCR100.dll is missing from your computer. Try reinstalling the program to fix this problem.
I searched the disk and found a copy of msvcr100.dll at C:\Program Files\sqldeveloper-22.214.171.124.64-x64\sqldeveloper\jdk\jre\bin\msvcr100.dll.
I then copied the above file to C:\Program Files\sqldeveloper-126.96.36.199.64-x64\sqldeveloper\sqldeveloper\bin\msvcr100.dll
I then double-clicked the main sqldeveloper executable again, and this time it started without errors.