On Cores running on Windows Server 2016 or Windows 10, if you attempt to create a repository larger than 16 TB with Write caching policy On (default and recommended setting), it fails. If you try to create a repository larger than 16 TB with Write caching policy Off, it is successful.
For the failed attempt you find an error in AppRecovery Logs similar too:
ERROR 2017-03-01T11:46:54  - ServiceHost.InMemoryHosting.InMemoryServiceHost ()
Method 'VerifyFileSpecifications' of service 'Replay.Core.Contracts.Repositories.IRepositoryManagement' failed
System.Reflection.TargetInvocationException depth 0: Exception has been thrown by the target of an invocation. (0x80131604) ---> System.InvalidOperationException depth 1: It is not possible to use a 29.3 TB large file to create a repository that has the write caching policy set to 'On' within the Windows Server 2016 operating system. Set the repository write caching policy to 'Off' or use multiple files of a size that does not exceed 16 TB to achieve the required total repository size. (0x80131509)
at Replay.Core.Implementation.Repositories.RepositoryServiceValidationHelper.VerifyWriteCachingPolicy(String path, WriteCachingPolicy policy, UInt64 repositorySize) +0xa7 600343f
This defect will be resolved in a future release of Rapid Recovery.