Ctrl+S (on a Mac ⌘S) or Actions → Export… → “Data backup (JSON)” saves the whole family tree with photos. Every save downloads a new .json file; in Chrome and Edge the tree can be linked to one file and saved into it again and again. The file belongs in the cloud or on another disk, and it opens on any device.
How often to save →An icon, installation and bookmark are convenience, not a backup.
| Device · browser | Where the data is | What deletes it |
|---|---|---|
| Computer · Chrome or Edge, tab | Where the data isin the browser profile | What deletes itclearing site data (cookies and site data); the “delete data on close” setting, unless Strom is among the exceptions; the browser itself when space runs out |
| Computer · Chrome or Edge, installed app | Where the data isthe same data as the tab | What deletes itthe same, and also uninstalling with “Also clear data from Chrome” ticked (Edge asks about deleting the app’s data) |
| Computer · Firefox | Where the data isin the profile | What deletes itthe “delete data on close” setting, unless Strom is among the exceptions; space running out |
| Mac · Safari, tab | Where the data isin Safari | What deletes itafter 7 days of using Safari without a visit to Strom; Safari → Settings → Privacy → “Manage Website Data” → Remove; space running out |
| Mac · Safari, app in the Dock | Where the data isits own data, not Safari’s | What deletes itthe data is deleted in the app itself: its name in the menu bar → Settings → Privacy; deleting the app from Applications (the data can no longer be reached); whether the 7 days apply, Apple does not say |
| iPhone and iPad · Safari (and every browser on iPhone), tab | Where the data isin Safari | What deletes itafter 7 days of using Safari without a visit |
| iPhone and iPad · on the home screen | Where the data isits own data, not Safari’s | What deletes itdeleting the icon; iOS does not guarantee the storage |
| Android · Chrome, tab and app | Where the data isthe same data | What deletes itclearing site data, in the installed app too. Before uninstalling: a backup saved to a file. |
| Everywhere · private (incognito) window | Where the data isonly until it is closed | What deletes itclosing all private windows |
“Only in browser” at the top means changes that are in no file yet; a click opens the “Where the data is” window. Without the label, a file may still be missing.
Step by step for each device is in the app guide.
| Installed | What changes |
|---|---|
| iPhone and iPad · icon on the home screen | Its own data, separate from Safari: a family tree from Safari moves over only by export and import. The 7 days of Safari do not apply to it; deleting the icon deletes the data. |
| Mac · Safari, Add to Dock | A separate app with its own data, separate from Safari. Deleting the app from Applications leaves its data out of reach. |
| Computer · Chrome or Edge | The same data as the tab. Uninstalling offers to delete the data too. |
| Android · Chrome | The same data as the tab; clearing site data deletes it in the app too. |
After every larger change; a few copies in different places (disk, flash drive, cloud).
Partial exports don’t count: a cut-out of the family tree, CSV, or an export with living people hidden.
Only via a file: export → transfer → open. No account, no QR.
The family tree is usually not lost: it is somewhere other than where Strom just opened. The app cannot tell and shows an empty tree.
An empty Strom shows “Welcome to Strom” with the “Add first person” button and the “I have data elsewhere (GEDCOM from MyHeritage, Ancestry…)” link.
Chrome does not see what is in Safari, and a work profile does not see a personal one. The family tree is in the browser and profile where it was entered.
stromapp.info, www.stromapp.info and a downloaded strom.html are three places for the browser. strom.html shares data with all HTML files opened from disk in the same browser.
A family tree entered earlier via www.stromapp.info is stored separately in the browser.
Each place has its own data. Moving only by export and import.
Closing all private windows deletes everything. Strom warns about it only in Safari and Firefox, not in Chrome and Edge.
The family tree does not move to another device by itself, not even by sync. Only via a file.
It happens after clearing site data, with delete-on-close, in Safari after 7 days of use without a visit, after deleting the icon, or when space runs out.
The way back is the latest backup file: “I have data elsewhere (GEDCOM from MyHeritage, Ancestry…)” → “From JSON”, or on a computer the file dragged onto the window. Backups inside the app vanished with the data. A phone backup does not reliably restore it.
Next time: same browser, same address, or same icon. On iPhone only the home-screen icon; on a Mac either always Safari or always the Dock. Elsewhere only from the file.