Symptoms
- 'No SIM' or 'SIM not installed' message appears right after updating
- No cellular signal even though it worked before the update
- SIM card looks fine and was working prior
- Airplane mode toggle doesn't resolve it
Likely causes
- CommonUpdate temporarily disrupted carrier settingsMajor OS updates sometimes require a fresh handshake with carrier network settings.
- CommonSIM card became loose during the update/restart processRestarts and updates can occasionally reveal an already slightly loose SIM tray.
- PossibleCarrier settings update needed but not yet installedPhones often prompt for a separate small carrier settings update after a major OS update.
- PossibleeSIM profile needs to be reactivatedOn eSIM-only phones, an update can occasionally require reselecting the active plan.
- Less commonPhysical SIM card or tray damageA damaged card or tray could coincidentally show symptoms right after an update.
What to do
- Restart the phone, which resolves this in most cases.
- Toggle airplane mode on and off.
- Check for and install a carrier settings update if prompted.
- Power off the phone, remove and reseat the physical SIM card, then power back on.
- For eSIM phones, check cellular settings to confirm the correct plan is still active and reselect it if needed.
- Reset network settings if the SIM still isn't detected (this clears saved Wi-Fi passwords too).
- Try the SIM in another compatible phone if possible to rule out a damaged card.
Tools and parts
- SIM eject tool or paperclip
When to call a pro
If the SIM tests as fine in another phone but this phone still won't detect any SIM, a repair shop should check the SIM reader hardware.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.