What causes "open clipboard timeout" in siyuan-note/siyuan?

Close other clipboard-monitoring tools (clipboard managers, RDP clipboard sync, screen-snipping tools) and retry.

open clipboard timeout

Error message

open clipboard timeout

What it means

Returned by waitOpenClipboard after retrying w32.OpenClipboard once per millisecond for up to one second. Windows enforces a single clipboard owner: only one process can hold the clipboard open at a time, so OpenClipboard fails while another app (clipboard viewer, remote-desktop tool, antivirus) has it open.

Source

Thrown at kernel/util/clipboard_windows.go:161

			binary.LittleEndian.PutUint16(buf[offset:offset+2], c)
			offset += 2
		}
	}
	return buf, nil
}

// waitOpenClipboard 在限定时间内重试打开剪贴板。
// 同一时刻仅一进程可持有剪贴板（OpenClipboard 成功）。
// https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-openclipboard
func waitOpenClipboard() error {
	deadline := time.Now().Add(time.Second)
	for time.Now().Before(deadline) {
		if w32.OpenClipboard(0) {
			return nil
		}
		time.Sleep(time.Millisecond)
	}
	return errors.New("open clipboard timeout")
}

View on GitHub (pinned to 251596fc0d)

Solutions

Close other clipboard-monitoring tools (clipboard managers, RDP clipboard sync, screen-snipping tools) and retry.
Retry the copy operation — the lock is usually brief and a second attempt shortly after often succeeds.
If the contention is persistent, raise the retry window or retry at the caller level rather than lengthening the tight loop.

Example fix

// before
if err := util.WriteFilePaths([]string{absPath}); err != nil {
    return err
}

// after
var err error
for attempt := 0; attempt < 3; attempt++ {
    if err = util.WriteFilePaths([]string{absPath}); err == nil {
        break
    }
    time.Sleep(200 * time.Millisecond)
}

Defensive patterns

Strategy: retry

Try / catch

var err error
for attempt := 0; attempt < 3; attempt++ {
    if err = util.WriteFilePaths(paths); err == nil || !strings.Contains(err.Error(), "open clipboard timeout") {
        break
    }
    time.Sleep(300 * time.Millisecond)
}

Prevention

Close clipboard-monitoring utilities and RDP clipboard sync before large copy operations.
Surface 'clipboard busy, retrying' to the user instead of failing on the first timeout.

When it happens

Trigger: Calling WriteFilePaths on Windows while another process holds the clipboard open for longer than 1 second. The 1-second deadline in waitOpenClipboard is exceeded before OpenClipboard succeeds.

Common situations: A clipboard-monitoring utility (e.g. a clipboard manager, snipping tool, or RDP/Teams clip-share) holding the clipboard; antivirus inspecting clipboard contents; rapid repeated copy operations; running under a remote-desktop session that synchronizes the clipboard.

Understand the failure class

Timeouts: ETIMEDOUT, deadlines, and hung requests — what actually expires when a request times out.

Related errors

AI-assisted analysis of siyuan-note/siyuan@251596fc0d (2026-08-12). Data as JSON: /api/errors/441794f7afa389c1. Report an issue: GitHub.