When ChatGPT memory is full, do not wipe everything at once: open Settings, then Personalization, then Memory, then Manage, and delete entries one by one, starting with outdated preferences, one-off project details and old entries that newer decisions have replaced. Keep only identity, long-term preferences and active project context. A full wipe makes it forget your habits, and you will have to re-explain everything every time.
First, work out which limit you actually hit
People mix up three different things. Saved memories are the list you can see in settings; it has a capacity limit, and once full, new memories cannot be saved and existing ones may not even be editable or removable until space is freed. A single overlong conversation is a context-window issue instead; starting a new chat or asking for a summary helps, and deleting memories does nothing for it. Chat history storage is a third thing, unrelated to the memory list. Deleting a chat does not delete its memories, and deleting a memory does not delete the original chat. Identify which one you are stuck on before touching anything.
Delete in this order to avoid mistakes
Step one: back up first. Copy the whole memory list into your own document, or run a data export from Data Controls and keep the archive, which includes memory entries. Deleted memories cannot be recovered, so save a copy before deleting; if you remove the wrong one, you can re-add it manually from the backup.
Step two: delete outdated preferences. A former employer, an old address after moving, eating habits you changed, temporary requirements from finished projects. Left in place, these do more than take space; the assistant keeps acting on stale facts, like drafting email in your old company's tone.
Step three: merge duplicates and superseded entries. If the same preference exists in two or three versions, keep only the newest. You can also ask in chat for a memory to be updated, but when memory is already full those edits may fail, so freeing space manually first is safer.
Step four: confirm what stays is long-lived: how to address you, your usual language and tone, your work role, background on long-running projects, and boundaries you have explicitly set. Keep those five kinds and daily use barely changes.
How to stop it filling up again
Use Temporary Chat for one-off tasks; that mode creates no new memories and does not use saved ones, so quick lookups and edits stop clogging the list. Build the habit of saying remember this for things that matter and do not remember this for things that do not. Spend two minutes a month scanning the list and clearing what expired; it is far cheaper than a big cleanup after it fills. One more rule, unrelated to capacity but more important: if the list contains something you never said, or something plainly wrong, delete it on sight. The model inferred it incorrectly, and leaving it there will keep bending future answers.
