Now that UT4 has updated to UE 4.11, all previously distributed community maps will no longer run in-game. This is all part of the #PreAlpha process so it’s part of the game for mappers right now.
Unfortunately, a bug has crept into the 2/1/16 UT Editor release that removed compression from the PAKing process. This has led to community made maps doubling in size and will undoubtedly slow the re-release of maps that are farther along towards completion due to slow download times from servers.
The good news is the bug has been logged and fixed and is now off to QA so hopefully we’ll get at least a hotfix for the Editor here shortly.