Symptoms
- Update fails partway with a storage error
- Phone shows storage full only during the update process
- Update completes but storage seems oddly reduced afterward
- Update won't even begin downloading due to space
Likely causes
- CommonUpdate requires significantly more temporary space than its final installed sizeThe system needs room to prepare and verify the update alongside the current OS before replacing it.
- CommonStorage was borderline before starting, without enough bufferHaving just barely enough space for the download itself isn't enough for the full process.
- PossibleCached files not clearing automatically to make roomSome temporary files that should be cleared automatically can occasionally linger.
- PossiblePhotos or videos not yet backed up to the cloud taking up local spaceMedia that hasn't been offloaded still counts against local free space.
What to do
- Free up several GB more than the update's stated download size, as a safety buffer.
- Back up and offload photos/videos to the cloud or a computer, then delete local copies.
- Delete unused apps, especially large ones like games.
- Clear browser and app caches to free additional temporary space.
- Restart the phone before trying again to ensure a clean, fresh amount of available space is calculated.
- Try the update again once well above the minimum required free space.
- Consider updating via a connected computer instead, which can be more storage-efficient during the process.
Tools and parts
- Computer with cable (optional)
When to call a pro
If an update genuinely can't complete due to space on a phone with limited storage, updating via computer is the most reliable workaround.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.