No microphone permission
Microphone mode requires a secure connection, browser support and your permission. Use the browser's site controls to check whether microphone access was blocked, and confirm the intended input in TuneGuitar's selector. A permission decision can also be affected by operating-system settings. Reference tones remain available without microphone access. If the browser never offers an input at all, use reference mode while resolving the device permission rather than repeatedly pressing the same start button.
Permission is granted, but there is no useful signal
Look at the input indication while plucking a single open string. An unmoving signal suggests the wrong input, a disconnected interface, a muted device or insufficient level. An electric guitar can be too quiet for a distant laptop microphone. Move closer or use a clean amplifier at a moderate level. Avoid placing the microphone directly against a loud speaker. Change distance before changing tuning, then compare the same note with the same attack.
The note flickers between strings
Mute every string except the one being measured. Stop backing tracks and the tuner's reference playback. Select the string manually so the target remains explicit. If the reading becomes stable, the experiment points to competing sound rather than a faulty tuning peg. Remember that a ringing neighbour may continue vibrating by sympathy even if you did not pluck it. A quiet room is useful, but deliberate string muting can matter just as much.
The letter is right but the octave is wrong
A guitar produces a fundamental and harmonics. The second harmonic is twice the frequency, which is the same note an octave higher. A low E2 may therefore appear as E3 when the fundamental is weak. Do not lower the string an octave to chase that reading. Reduce effects, reposition the microphone and check the selected target. Low-register and paired-string setups particularly benefit from individual string isolation. The octave issue is about which component is detected, not automatically about a string being too tight.
The pitch starts sharp, then settles
Repeat a moderate pluck and watch the same part of the sustain. A strong attack changes the transient behaviour, while the quiet tail can be difficult to measure. If a consistent settled region exists, use it. If a normally fretted note becomes much sharper than the open check, investigate playing pressure or the instrument's setup. Lowering the string to make the strongest first instant look centred can leave the sustained musical note flat.
A perfect reading that seems too easy
Stop all reference tones and backing audio, mute the guitar and check that the reading disappears. If it continues, another sound may be feeding the microphone. The correct note coming from a loudspeaker can create a false sense that your own string is correct. Repeat the measurement with the guitar alone. Headphones can keep backing audio out of the microphone, but they do not remove the need to isolate unplayed strings.
When the problem needs a different test
Once the open string is detected steadily, use the intonation tool only if fretted notes remain suspect. Use the known-reference tool if you have an independently known frequency and want to examine measurement error. Neither test replaces identifying the right input. Record the browser, device, selected input, preset and exact symptom if you report a problem through the contact link. Do not send microphone recordings or private setup links unless you intend to share their contents.