After this fix is applied: 5bb0164 which fixes /issues/15089

there is another problem that prevents windows users with usernames that are cyrillic/unicode using bitcoin core:

2019-01-03T21:42:16Z * Using 2.0MiB for block index database
2019-01-03T21:42:16Z * Using 8.0MiB for chain state database
2019-01-03T21:42:16Z * Using 440.0MiB for in-memory UTXO set (plus up to 286.1MiB of unused mempool space)
2019-01-03T21:42:16Z init message: Loading block index...
2019-01-03T21:42:16Z Opening LevelDB in C:\Users\Даниелька\AppData\Roaming\Bitcoin\blocks\index
2019-01-03T21:42:16Z Fatal LevelDB error: IO error: C:\Users\Даниелька\AppData\Roaming\Bitcoin\blocks\index\LOCK: Could not lock file.
2019-01-03T21:42:16Z You can use -debug=leveldb to get more complete diagnostic messages
2019-01-03T21:42:16Z Fatal LevelDB error: IO error: C:\Users\Даниелька\AppData\Roaming\Bitcoin\blocks\index\LOCK: Could not lock file.
2019-01-03T21:42:16Z : Error opening block database.
Please restart with -reindex or -reindex-chainstate to recover.

Running bitcoind.exe and bitcoin-qt.exe as administrator fixes this issue but this should not be required - it's like having to run something as root on linux.

Running the same bitcoind.exe and bitcoin-qt.exe on windows with a standard windows username (no special characters) works fine without having to run as administrator.

Tested using Windows 10 64bit and the latest Master branch using the cross compile guide with the patch 5bb0164

You can test on windows by just creating a new user called "Даниелька" (copy and paste it).

The prebuilt binaries [https://bitcoin.org/bin/bitcoin-core-0.17.1/bitcoin-0.17.1-win64.zip] work without having to run as admin.