What causes "Langs[Lang][266]" in siyuan-note/siyuan?

Install tesseract-ocr (plus required language packs, e.g. tesseract-ocr-chi-sim) and make sure it is on PATH, then restart SiYuan

siyuan-note/siyuan · info

Langs[Lang][266]

Error message

Langs[Lang][266]

What it means

OcrAsset performs Tesseract OCR on an image asset, but only when the TesseractEnabled flag is set (requires the tesseract binary to be found/configured). When OCR is disabled, it returns a localized message from Langs[Lang][266] — the i18n string telling the user OCR is not enabled — instead of running OCR. It is an expected precondition failure, surfaced to the UI as a localized notice.

Solutions

Install tesseract-ocr (plus required language packs, e.g. tesseract-ocr-chi-sim) and make sure it is on PATH, then restart SiYuan
Enable the OCR setting in SiYuan (Settings - Assets - OCR / enable Tesseract) after installation
If OCR is intentionally off, stop issuing OCR requests; the error is expected in this state
In containerized deployments, switch to an image variant that includes tesseract or add it to the Dockerfile

Example fix

// before
texts, _ := util.OcrAsset(asset) // error: OCR not enabled
// after
if util.TesseractEnabled {
    texts, err := util.OcrAsset(asset)
    if err != nil { return err }
} else {
    return errors.New("tesseract OCR is not installed or disabled; install tesseract-ocr and enable it in settings")
}

Defensive patterns

Strategy: fallback

Validate before calling

// Go: skip OCR work when Tesseract is not enabled
if !util.TesseractEnabled {
    return nil // or handle asset without OCR text
}

Try / catch

texts, err := util.OcrAsset(asset)
if err != nil {
    if strings.Contains(err.Error(), util.Langs[util.Lang][266]) {
        logging.LogWarnf("OCR disabled, skipping asset %s", asset)
        return nil
    }
    return err
}

Prevention

Install tesseract-ocr and language packs before enabling OCR-dependent features
Verify tesseract is on PATH at deployment time and check TesseractEnabled after kernel startup
Gate OCR-calling code paths on util.TesseractEnabled so disabled OCR degrades gracefully
In Docker, use an image variant that ships tesseract or add it explicitly to the image build

When it happens

Trigger: Calling OcrAsset (directly or via the OCR-related API/anonymous caller in asset indexing) when TesseractEnabled is false — i.e. the tesseract executable was not detected at startup or OCR was turned off in settings, yet an OCR request/asset-text rebuild was issued.

Common situations: Tesseract not installed on Linux server/desktop builds (SiYuan does not bundle it everywhere); PATH lacking the tesseract binary; user invokes 'extract image text' or rebuilds asset OCR index after disabling OCR; Docker image without tesseract installed.

Related errors

AI-assisted analysis of siyuan-note/siyuan@9f775e8a12 (2026-09-19). Data as JSON: /api/errors/a3e0f0c4f2b9c27b. Report an issue: GitHub.

Appendix: source

Thrown at kernel/util/ocr.go:161

	assetsTextsLock.Lock()
	oldText, ok := assetsTexts[asset]
	assetsTexts[asset] = text
	assetsTextsLock.Unlock()
	if !ok || oldText != text {
		assetsTextsChanged.Store(true)
	}
}

func ExistsAssetText(asset string) (ret bool) {
	assetsTextsLock.Lock()
	_, ret = assetsTexts[asset]
	assetsTextsLock.Unlock()
	return
}

func OcrAsset(asset string) (ret []map[string]string, err error) {
	if !TesseractEnabled {
		err = errors.New(Langs[Lang][266])
		return
	}

	assetsPath := GetDataAssetsAbsPath()
	assetAbsPath := strings.TrimPrefix(asset, "assets")
	assetAbsPath = filepath.Join(assetsPath, assetAbsPath)
	ret = Tesseract(assetAbsPath)
	assetsTextsLock.Lock()
	ocrText := GetOcrJsonText(ret)
	assetsTexts[asset] = ocrText
	assetsTextsLock.Unlock()
	if "" != ocrText {
		assetsTextsChanged.Store(true)
	}
	return
}

func GetAssetText(asset string) (ret string) {

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