After a (clean) server shutdown/reboot our MongoDB-Server fails to start with the follow messages:

2017-06-26T12:11:28.491+0200 E STORAGE [initandlisten] WiredTiger error (-31802) [1498471888:491849][14448:0x7f796a509cc0], file:WiredTiger.wt, connection: unable to read root page from file:WiredTiger.wt: WT_ERROR: non-specific WiredTiger error
2017-06-26T12:11:28.491+0200 E STORAGE [initandlisten] WiredTiger error (0) [1498471888:491897][14448:0x7f796a509cc0], file:WiredTiger.wt, connection: WiredTiger has failed to open its metadata
2017-06-26T12:11:28.491+0200 E STORAGE [initandlisten] WiredTiger error (0) [1498471888:491907][14448:0x7f796a509cc0], file:WiredTiger.wt, connection: This may be due to the database files being encrypted, being from an older version or due to corruption on disk
2017-06-26T12:11:28.491+0200 E STORAGE [initandlisten] WiredTiger error (0) [1498471888:491916][14448:0x7f796a509cc0], file:WiredTiger.wt, connection: You should confirm that you have opened the database with the correct options including all encryption and compression options
2017-06-26T12:11:28.492+0200 I - [initandlisten] Assertion: 28595:-31802: WT_ERROR: non-specific WiredTiger error src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp 267

We've tried different repair attempts but all of them failed.
In other tickets we've seen that your may are able to repair the corrupt files.
Any help would be appriciated.

If you need any further details or files i'll provide them as soon as possible.

Thanks in advance.