Thunderbird Gmail IMAP: `[TRYCREATE] No folder [Gmail]/All Mail` (THROTTLED)¶

🛑 Problem¶

Thunderbird raises an error against a Gmail account:

The current operation on 'Inbox' did not succeed. The mail server for account
maj.linux@gmail.com responded:
[TRYCREATE] No folder [Gmail]/All Mail (Failure) [THROTTLED]

This is two distinct Gmail-side failures reported in one line, neither of which has anything to do with your self-hosted mail server (majormail / mail.majorshouse.com):

Token	Meaning
`[TRYCREATE] No folder [Gmail]/All Mail`	Thunderbird tried to access (or copy into) the All Mail IMAP folder, but Gmail isn't exposing it. The `[Gmail]/` namespace is Google-side, not your Dovecot server.
`[THROTTLED]`	Gmail is rate-limiting the account — too many simultaneous IMAP connections or too much traffic in a short window. Server-side; no client config makes it go away instantly.

🔍 Diagnosis¶

Step 1 — Confirm which account is throwing it¶

The error names maj.linux@gmail.com and the [Gmail]/All Mail path. Both are Google-specific. A self-hosted Dovecot account (e.g. marcus@majorshouse.com) uses a flat layout (Trash, Archives) with no [Gmail]/ strings, so it can never produce this error — even when both accounts live in the same Thunderbird profile.

⚠️ Don't confuse MajorMac (the Mac workstation) or majormail (the Dovecot server) with this. Recent Dovecot mail_home work and MajorMac SSH/WoL changes touch neither Gmail nor prefs.js mail config. See Dovecot Phantom Mailboxes — that was the majorshouse.com domain, a separate mailbox system.

Step 2 — Inspect the Thunderbird account config (optional, confirms isolation)¶

Thunderbird stores accounts in prefs.js inside the profile. On macOS:

PROFILE=$(ls -d ~/Library/Thunderbird/Profiles/*/ | head -1)
grep -E 'mail\.server\.server[0-9]+\.(hostname|type)' "$PROFILE/prefs.js"
grep -E 'mail\.identity\.id[0-9]+\.(useremail|archive_folder)' "$PROFILE/prefs.js"

(Linux: ~/.thunderbird/*.default*/prefs.js; Windows: %APPDATA%\Thunderbird\Profiles\*\prefs.js.)

A telltale sign the error is a subscription problem, not an archive-action problem: the Gmail identity's archive_folder points somewhere other than [Gmail]/All Mail (e.g. Local Folders/Archives). That means nothing is deliberately writing to All Mail — Thunderbird is only hitting it during routine folder sync, which is exactly what fails when "Show in IMAP" is off for that label.

✅ Fix¶

1. Expose All Mail over IMAP (Gmail side — the real fix)¶

Gmail web → Settings → Labels → find All Mail → check Show in IMAP. Do the same for any system label Thunderbird treats as Archive/Trash/Sent.

Right-click the Gmail account → Subscribe… → confirm All Mail is ticked → OK.

3. Reduce connection pressure (the `[THROTTLED]` half)¶

Account Settings → Server Settings → Advanced → set Maximum number of server connections to cache to 1 (default 5; Gmail dislikes high counts). Close other clients hammering the same account during the initial re-sync.

4. Wait out the throttle¶

[THROTTLED] is server-side and clears on its own — usually within an hour, occasionally up to ~24h. Until it lifts you may keep seeing it regardless of client config.

Restart Thunderbird after steps 1–3, then let it settle.

🔁 Why This Happens¶

Symptom	Cause
`No folder [Gmail]/All Mail`	"Show in IMAP" is disabled for the All Mail label, so Gmail won't serve that folder. `TRYCREATE` is the IMAP server hint "this folder doesn't exist — create it?", which a client can't do for `[Gmail]/` system folders.
`[THROTTLED]` appears alongside it	Gmail caps concurrent IMAP connections and ~2.5 GB IMAP download/day per account. Multiple clients (Thunderbird + phone + another desktop) or a high connection-cache count trip it.
Error references Gmail but you recently changed your own mail server	Coincidence of two separate accounts in one profile. The `[Gmail]/` namespace proves it's Google's, not Dovecot's.

⚠️ Key Notes¶

[Gmail]/ is always Google-side. No change to a self-hosted Dovecot/Postfix server can cause or fix a [Gmail]/… error.
One Thunderbird profile, multiple accounts, independent failures. A Gmail account and a majorshouse.com account coexisting in the same window do not share folder layouts or throttle state.
The throttle is the symptom of the connection count — dropping cached connections to 1 is the durable mitigation, not just unbanning/waiting.
TRYCREATE ≠ a missing folder you must create. For Gmail system folders the real action is flipping "Show in IMAP", not creating anything.

🔎 Quick Diagnostic Commands¶

# Locate the Thunderbird profile (macOS)
ls -d ~/Library/Thunderbird/Profiles/*/

# List configured accounts and identities
PROFILE=$(ls -d ~/Library/Thunderbird/Profiles/*/ | head -1)
grep -E 'mail\.server\.server[0-9]+\.(hostname|type)' "$PROFILE/prefs.js"
grep -E 'mail\.identity\.id[0-9]+\.useremail' "$PROFILE/prefs.js"

# Find any folder paths pinned to the Gmail All Mail namespace
grep -iE '\[Gmail\]|All Mail' "$PROFILE/prefs.js"

Thunderbird Gmail IMAP: [TRYCREATE] No folder [Gmail]/All Mail (THROTTLED)¶