Start inside Signal rather than deleting its app data. On Android, open your profile → Data and Storage → Manage storage → Review storage. Select attachments you no longer need. On iPhone, review media in the relevant conversation. Deleting an attachment is a content decision, not simply clearing a temporary cache.
Choose the action that matches the problem
| Your goal | Useful first step | What to check |
|---|---|---|
| Remove a large video | Find it in Signal’s media or storage review | Save any copy you need outside Signal first. |
| Reduce future accumulation | Review download and message-retention settings | A shorter retention period can remove conversation history. |
| Reinstall or change phones | Review the current backup or transfer options | Having an account or a linked desktop is not proof that the phone history can be restored. |
Review attachments without deleting a whole conversation
- Open Signal’s storage review on Android, or open the conversation’s media section on iPhone.
- Identify a large attachment and decide whether you still need it. Save an important file separately and check that the saved copy opens.
- Read the deletion confirmation. Start with a small selection rather than deleting every conversation.
- Compare Signal’s size in the phone’s storage settings after cleanup. A copied file can still occupy storage outside Signal.
The exact controls differ between platforms and versions. Signal’s storage documentation provides the platform-specific routes. Removing a local message or chat does not by itself remove it from the other person’s device.
Disappearing messages are not a cache cleaner
A timer changes how long eligible messages remain available; it is not a guarantee that Signal will stay below a particular size. Avoid changing the timer or retention settings solely to reach an advertised storage target. Decide what history you want to keep before confirming a shorter retention period.
Check recovery before any reinstall
Signal now documents optional Secure Backups. Check the Backups screen in your version and confirm what is actually enabled. Secure Backups use a recovery key: keep that key accessible before replacing the installation. Backup coverage has limits, so do not assume every attachment or disappearing message is included. Android on-device backups and device transfers are separate workflows.
A practical way to measure the result
Illustrative example: if the storage review identifies several large videos, deleting only those gives you a specific change to evaluate. Record the phone’s reported Signal size before and after. Do not describe the difference as a guaranteed amount for another phone. If the figure grows again, review new downloads and retained media rather than repeatedly reinstalling.
A photo-library cleaner works on files it can access in the photo library; it cannot directly erase Signal’s private messages or database. For another messaging app, use the separate Telegram storage guide.
Official references
Updated 6 November 2026. Instructions were checked against the linked documentation; examples illustrate a decision process, not a measured device test.
