After some in-place upgrades of TFS, program files now contains:
- Microsoft Team Foundation Server 11.0 (2,04 GB)
- Microsoft Team Foundation Server 12.0 (36,5 GB)
- Microsoft Team Foundation Server 15.0 (1,58 GB) <--- current
The 36 GB from version 12 resides mostly in folders named _tfs_data in TFSJobAgent and Web Services folders.
Is it safe to remove these?