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Fronius · PV inverters · Fronius Symo 3.0–20.0 (three-phase grid inverter, SnapINverter)

STATE 736Write or read error occurred

Name in the manufacturer's documentation (service manual): Write or read error occurred[1]

In plain words (editorial)

A write or read error occurred on the USB flash drive. The manual says to check the drive and its data or replace it, and never to unplug a drive while data is being transferred.

When to call a service technician: If the code is displayed all the time, notify a Fronius-trained service technician.

✎ editorial – written from the cited sources, not a manufacturer statement. Status: draft.

The Polish page has more detail (plain-language explanation, safe checks, guides): Read in Polish →

Sources

Every statement has a footnote to the document and PDF page. “Quote verified” means the quote was found automatically in the text of that page.

  1. [1] Fronius Symo 3.0-3 – 20.0-3, Fronius Eco 25.0-3 – 27.0-3 – Operating Instructions (42,0410,2028, ed. 016-24082016) – distributor copy (42,0410,2028 (016-24082016)) , p. 51 manufacturer document – copy from a distributor quote verified 736 Write or read error occurred
  2. [2] Fronius Symo / Fronius Eco – Operating Instructions (e-Manual HTML), Version 044-17072025 – chapter “Status diagnostics and troubleshooting” (text capture) (e-Manual 4204101909, 044-17072025) , p. 7 official manufacturer document quote verified Check USB flash drive and the data contained on it or replace USB flash drive Never unplug a USB flash drive if the 'data transfer' LED is still flashing or lit
  3. [3] Fronius Symo / Fronius Eco – Operating Instructions (e-Manual HTML), Version 044-17072025 – chapter “Status diagnostics and troubleshooting” (text capture) (e-Manual 4204101909, 044-17072025) , p. 7 official manufacturer document quote verified If the status code is displayed all the time: Notify a Fronius-trained service technician
  4. [4] Fronius Symo / Fronius Eco – Operating Instructions (e-Manual HTML), Version 044-17072025 – chapter “Status diagnostics and troubleshooting” (text capture) (e-Manual 4204101909, 044-17072025) , p. 7 official manufacturer document quote verified Warning message on the display