Invalid Characters in File Names

I have a mixed environment with OSX, OpenSuSE, and Windows. Invalid characters in file names always trouble me. Things got more complex when using with online storage service. That’s why I create this page to share my experience.

HFS Plus Invalid Characters

According to How Macintosh Filenames Are Translated on Microsoft, : (colon) is the only invalid characters in file names.

/ is not allowed in terminal due to Unix.

NTFS and ReFS Invalid Characters

According to Illegal Characters on Various Operating Systems and Semantic Differences Between Server for NFS and UNIX-Based NFS Servers on Microsoft TechNet, : ” \ / * ? < > | and any character type with [Ctrl] key are invalid characters in file names.

Wiki Filename provides more information when used as extension and in POSIX.

After testing ReFS on Thecus W5000, : ” \ / * ? < > |  is still not supported.

ext4 Invalid Characters

According to ext4 on Wiki, / NULL are invalid characters in file names.

Use NFS with Invalid Characters

When running NFS on NTFS, : ” \ * ? < > | will be translated by rules in character translation file. See detail in Configure File Name Character Translation in Server for NFS to Support a UNIX-to-Windows Migration on Microsoft and File Name Translation revisited on Microsoft TechNet Blog.

Files contains ” \ / * ? < > | won’t be copied from OSX to NTFS via NFS, Finder will stop you.

Use Samba with Invalid Characters

Files contains ” \ / * ? < > | are valid transfer from OSX to NTFS via Samba but becomes . when checked on Windows. You may copy them back to OSX with these invalid characters, it keep these characters instead of just .. If you browse them via NFS on NTFS, they won’t be visible.

Box.com Invalid Characters

According to Box Sync 3.x Behavior, Limitations, and Recommendations and Box Sync 3.x Behavior, Limitations, and Recommendations on BoxHelp, : ” \ / * ? < > | & _ are invalid characters in file names to BoxSync.

OneDrive Invalid Characters

According to Invalid characters in file or folder names, or invalid file types in OneDrive for Business, for OneDrive for Business on Office 365, SharePoint Online, and SharePoint Server 2016 : ” \ / * ? < > | are invalid characters in file names; on SharePoint Server 2013, : ” \ / * ? < > | ~ & { } % # . are invalid characters in file names.

Feedback from van nilla

As of June 2017, the new default for onedrive is to allow percent symbol % in filenames.
In some cases, admins will need to enable this. The number-pound symbol # is still not allowed, sigh.

Reference

1. Acronis: 39790: Illegal Characters on Various Operating Systems
2. Apple: OS X
3. Apple: Support: Mac Basics: The Finder organizes all of your files
4. Box.com: BoxHelp: Box Sync 3.x Behavior, Limitations, and Recommendations
5. Box.com: BoxSync
6. Microsoft: Appendix E – How Macintosh Filenames Are Translated
7. Microsoft: MSDN: Resilient file system
8. Microsoft: Office: Support: Invalid characters in file or folder names, or invalid file types in OneDrive for Business
9. Microsoft: Office 365
10. Microsoft: OneDrive for Business
11. Microsoft: SharePoint 2013
12. Microsoft: Support: HOW TO: Configure File Name Character Translation in Server for NFS to Support a UNIX-to-Windows Migration
13. Microsoft: TechNet Blog: File Name Translation revisited
14. Microsoft: TechNet: Semantic Differences Between Server for NFS and UNIX-Based NFS Servers
15. OpenSuSE
16. Samba
17. Thecus: W5000
18. Wiki: ext4
19. Wiki: Filename
20. Wiki: HFS Plus
21. Wiki: Network File System
22. Wiki: NTFS
23. Wiki: POSIX
24. Wiki: Unix