Threadstow saves the conversations that reach your Mac, photos and voice notes included, into an archive on your Mac. When the phone is full, it shows you which conversations are safe to let go. You decide what goes.
Release in preparation for macOS 15 and later. The archive never leaves your Mac.
D
DadFebruary 12, 2021
✓ Verified
Dad’s Sunday pastaOne lemon. A little patience.
A little more lemon. Trust me.
Okay, you were right. Again.
M
MayaOctober 3, 2023
✓ Verified
Voice message · 0:14
I got the keys. It’s really happening.
I’m bringing the first plant.
CC
The coast crewAugust 18, 2019
✓ Verified
Same place next summer?
Every summer.
Fictional conversations. Click a card to bring it forward.
The rule
Where a message comes from decides what the app may say about it.
Live capture keeps the archive up to date every day. Only a Finder backup can tell Cleanup what is on the phone. Cleanup ranks conversations by the space they take there and says why any row is not safe yet. Switch between the two and tick the conditions to see when a conversation counts as safe.
◱Your iPhone
Messages, photos and voice notes live here. The app never connects to it and never writes to it.
Finder backup: not imported
no connection to the phone
▭Messages on this Mac
Messages on the Mac is a synced copy of the phone, not a separate archive. With Full Disk Access, the app reads it while it is running.
Live capture onOriginal files never changed
copied, then verified
▤Threadstow archive
A folder on your Mac that only ever grows. Each attachment is checked byte for byte against its source.
213 messages archived13 of 14 attachments verified
What Cleanup needs before it says “safe”
!Never from live capture
Live capture only sees what reached this Mac. It cannot know what is on the phone, so Cleanup will not judge this conversation until a backup is imported.
A fictional conversation. Nothing on this page deletes anything, and neither does the app.
01
Messages arrive. The archive keeps them.
Grant Full Disk Access once. While the app runs, it watches Messages on this Mac and copies new conversations, with the attachments the Mac has downloaded, into a separate archive.
The app reads the original Messages files and never changes them. Pause or resume any time in Settings › Sources.
02
Every photo is checked against the original.
Each saved attachment is compared, byte for byte, with the file it came from. A file the Mac has not downloaded yet is marked as waiting and checked again later.
A verified file means the copy is good. It does not yet mean the phone can be cleared.
03
Before you clear the phone, one backup.
Make a backup in Finder, encrypted or not, and import it. That is the only complete picture of what is on the iPhone, so Cleanup works from it and can add attachments the Mac never had.
Then you delete in Messages. Threadstow never deletes anything for you.
ConversationsLive capture on
The coast crewiMessageCapturing
Cleanup · backup of Sep 21
✓All 213 messages in the archive
✓14 attachments verified against the backup
!Archive backed up? Check Time Machine first
Safe to delete. You delete in Messages.
What you keep
A shoebox that can be searched.
It is not a chat app and it is not a cloud service. It is a folder on your Mac that holds every conversation, with the photos and voice notes that came with it, and it can do a few things Messages cannot.
Search with filters
Search for a phrase or the start of a word, combine words with AND, OR and NOT, and filter by who sent it, when, what was attached and how big it is. from:Sam has:video before:2020 finds the videos Sam sent you before 2020.
Names for numbers
A number you never saved gets a suggested name from your iPhone’s contacts, Contacts on this Mac, cards people sent you and introductions in messages. Each suggestion shows where it came from. You accept it, or give anyone a name of your own.
Every kind of message
Conversations from iMessage, SMS and RCS, with replies, reactions, stickers and group events where they were. An edited message keeps every earlier version, and an unsent one keeps whatever was captured before the unsend. A message still in Recently Deleted on the phone stays in the archive, marked as such.
Live Photos
The picture and its motion are both kept and verified. The motion comes from the iPhone backup, so a Live Photo waits for one before its conversation is called safe.
The gallery, largest first
Every photo, video, voice message and file, filtered by kind and sorted by size, so the videos filling the phone are one click away. Press Space for Quick Look, reveal a file in Finder, or export a selection under the original names.
Every link anyone sent
Every link anyone sent, in one list you can filter by domain. Click one to open it in your browser. Threadstow never fetches a preview.
Removal confirmed
After you delete, import the next backup. Threadstow reports what left the phone and confirms that every one of those messages is still in the archive.
Export and walk away
Export any conversation as HTML, PDF or JSON, with reactions, replies and edits in place and the attachments beside it. The HTML export opens in any browser.
Stays on your Mac
The archive is a folder you choose, on a drive you own, encrypted if you like. You can move it with every file verified on the way, check it again any time, and let Time Machine back it up. There is no account, and nothing leaves your Mac unless you turn on a name source, crash reports or an AI assistant yourself.
Ask the AI assistant you already use
Let an assistant on this Mac, such as Claude Desktop or Claude Code, search the archive and answer a question like "when did Sam last mention the cabin". Assistants connect through MCP, and it is off until you turn it on. The server answers only on this Mac. Each assistant gets a connection of its own, which you can pause or revoke, and a new connection sees names, dates, counts and short excerpts. Whole messages and attachment files are separate switches, off until you turn them on. No assistant can change, delete or send anything. You can hide any conversation from all of them from the conversation list, and what an assistant reads goes to the service behind it.
Everything can be reached from the keyboard, and the app works with VoiceOver, Differentiate Without Color and Reduce Motion. The help is built in, and pausing capture is one click in Settings › Sources.
Keep the conversation around the photo.
A summer photo means more with the messages around it. Keep those, whether they hold a family recipe or the first piece of good news.
Questions
Before you let anything go.
Live Messages or an iPhone backup?
Both, and they do different jobs. Live capture keeps the messages that reach this Mac every day. A Finder backup tells Cleanup what is actually on the phone. The app reads local files only. It does not connect to your iPhone or to iCloud.
Does it delete messages for me?
No. You delete in Messages. Import a recent backup and read Cleanup first. Live capture alone never marks a conversation safe to delete.
What does “verified” mean?
The saved attachment matches the bytes read from its source. Cleanup still blocks removal guidance for missing files, unreadable messages or unfinished checks.
Will this keep every message on my iPhone?
Only items available in a source can be archived. Attachments this Mac has not downloaded are marked as waiting, then retried. A Finder backup can supply files the Mac lacks, if the backup contains them.
Do I need to encrypt the backup?
No. Threadstow reads both kinds. Encryption is recommended, because it protects the backup while it sits on your Mac, and Finder includes more of your data in an encrypted backup. Threadstow asks for the password at each import and forgets it afterwards, unless you tick Remember in Keychain.
What if I change iPhones, or have more than one?
Import each phone’s backup. Messages from all of them merge into one archive, one conversation per person or group, and no message or file is stored twice.
What if I use Messages in iCloud?
Deleting a synced conversation removes it from every device. Your archive is separate, but files that exist only in iCloud must be downloaded to this Mac, or be in the backup, before they can be archived.
Where is my archive?
In a folder on your Mac, shown in Settings › Storage. Move it to another drive from there. iCloud Drive and Dropbox folders are not supported, because they can remove a file’s contents from the Mac.
What leaves my Mac?
Nothing, unless you turn it on. There is no account, no server and no analytics. Crash reports are off until you switch them on, and carry no message text. Two optional name sources send data: Microsoft 365 receives one number or address per search, and a language model you choose receives up to the last 30 messages of the one conversation it is asked about. If you let AI assistants read the archive, they connect from this Mac only, and what they read goes to the service behind them.
Can AI assistants read my archive?
Only if you turn it on in Settings › Agents and add a connection for the assistant. A new connection sees conversations, names, dates, counts and short excerpts around the words it searches for. Whole messages and attachment files are separate switches for each connection, off until you turn them on. No assistant can change, delete or send anything, the server answers only on this Mac, and you can hide any conversation from all assistants. What an assistant reads goes to the service behind it.
Can I pause live capture?
Yes. Settings › Sources has Pause, Resume and Update Now. Live capture needs Full Disk Access, a readable Messages database on this Mac and the app running.
Can I export my conversations?
Yes. Export to HTML, PDF or JSON. Your archive remains yours even if you stop using the app.
