Advapi32Util has 2 methods that wrap the above mentioned API calls - getAccountBySid/Name respectively. The 2 methods work more or less the same - they make an initial call to the LookupAccountXXX method in order to query how much memory they need to allocate. The code expects the initial call to fail with an error code of ERROR_INSUFFICIENT_BUFFER (122). The code checks this by invoking Kernel32.INSTANCE.GetLastError().

Here is the strange bit: the call to LookupAccountXXX does fail, but the reported error code from the Kernel32.INSTANCE.GetLastError() invocation is zero - i.e., success. If I replace the call to Kernel32.INSTANCE.GetLastError() with Native.getLastError(), then indeed ERROR_INSUFFICIENT_BUFFER is reported and the code continues successfully.

This behavior is reproduced every time on my computer - Windows 10 Home edition 64 bit with VS 2015 update 1 - whenever I run Advapi32UtilTest#testGetAccountBySid/Name (respectively).