Folders with special characters

Why a folder with umlauts or other special characters may appear in FOLD but not open, and what you can do.

Folder names such as “Entwürfe”, “Größe” or “Årsrapport” travel between FOLD and your server in an encoded form. Most servers handle this correctly. A few do not, and then a folder can appear in FOLD without working.

How FOLD handles folder names

IMAP transmits characters outside plain ASCII in a special encoding called modified UTF-7: “Entwürfe” becomes Entw&APw-rfe. FOLD decodes the names when it reads your folder list, stores them in the standard composed Unicode form (NFC), and encodes them again whenever it addresses a folder. Names with spaces, parentheses, quotes, percent signs or asterisks are sent quoted.

FOLD does not switch servers into their optional UTF-8 mode; it always uses this encoding.

When it goes wrong

Some servers list folder names differently:

• as raw UTF-8 instead of modified UTF-7, or
• in decomposed Unicode form (NFD), where “ü” is stored as “u” followed by a separate diaeresis.

FOLD then shows the folder with the right name, but the name it sends back differs from what the server stored, and the server answers that the folder does not exist. FOLD does not yet remember the exact form in which a server listed a name.

Symptoms

• The folder appears in the sidebar but stays empty or cannot be opened.
• On the Mac, a bar reports Sync failed: for that folder.
• Moving messages into the folder or renaming it fails, for example with Move failed. on iPhone and iPad.
• Other folders of the same account work normally.

What you can do

1. Rename the folder on the server to a name without special characters, using your provider’s webmail or another mail app. FOLD picks up the new name at the next sync.
2. Tell your provider. Servers should list names in modified UTF-7, as the IMAP standard requires.

When you create or rename a folder in FOLD, the name must not contain “/”. Subfolders move with their parent when you rename it.