How to auto-reload a file when it changes on Mac
Note My can follow a file that something else keeps rewriting and reload it silently as it changes. Here is where the switches actually are, and the one case that will always stop and ask you first.
A build writes to the same file every thirty seconds. A script regenerates a config. A colleague saves over a shared file on a mounted volume. You switch back to the editor and get asked, again, whether you want to reload — or worse, you are not asked at all and spend ten minutes reading a stale copy.
Both halves of that problem are the same setting. Note My keeps an eye on every open file that has a path on disk, and a small set of switches decides what happens when one changes underneath you. All of it happens on your Mac: nothing is uploaded, there is no account, and a file you are watching never leaves the machine.
The three modes: Ask, Auto-Reload, Never
What Note My does when a watched file changes is governed by a single mode, and there are exactly three.
| Mode | What happens when the file changes |
|---|---|
| Ask (default) | A sheet appears offering Reload or Keep My Version. You decide each time. |
| Auto-Reload | The tab is brought up to date with what is on disk, silently. No sheet, no interruption. |
| Never | Nothing happens and nothing is said. What you are looking at stays exactly as it is until you reload it yourself. |
Never is not the same as switching monitoring off. The file is still watched and deletion is still reported; what Never does is stop a rewritten file from interrupting you.
Which mode you want depends on whether you are reading the file or writing it. Auto-Reload suits an output you only look at, such as a report a script regenerates. Ask suits anything you type into. Never suits a reference copy you want to keep still.
Where the controls actually live
The status-bar file-monitor badge. At the bottom of the window, beside the counters, sits a small badge for the active tab. Its menu carries the monitoring controls for the file in front of you, and the badge itself reports the state. When more than one is true, the one nearest the top of this list wins.
| State | Meaning |
|---|---|
| File missing | The file is no longer at its path. |
| External change pending | A change was seen and is waiting on your answer. |
| Disabled | Monitoring is off for this file. |
| Following tail | The tab is pinned to the end of a growing file. |
| Auto-reloading | Changes are being taken silently. |
| Watching | The ordinary state. Nothing to report. |
Settings ▸ File Monitor. Press ⌘, and choose File Monitor in the sidebar. This is where the defaults for every file live: the master Watch open files switch, the mode, how often files are checked for changes, whether unsaved edits force a prompt, whether a deleted file is reported, and whether logs update themselves.
Set it up
-
Confirm monitoring is on before you open the files
The master switch is on by default, so usually there is nothing to do and every file you open is watched from the moment it appears. If you have just turned the switch on yourself, close any tabs that were already open and open them again; from that point on the whole session is covered.
-
Choose the mode
In Settings ▸ File Monitor, set the external-change mode. Ask is the default and the right choice while you are editing. Auto-Reload is what you want when the file is an output you are reading rather than a document you are writing.
-
Set how often files are checked
The default is 3 seconds, settable from 1 to 600 seconds. Shorter means a change on a network volume reaches you sooner. On a local disk you can leave it where it is; changes there show up promptly at any setting.
-
Decide what unsaved edits should do
Leave the warn-on-unsaved setting on unless you have a reason not to. With it on, a change that arrives while you have unsaved edits always prompts, whatever the mode says. Whatever you choose here, ⌘R still reloads the tab on demand.
The one case that always asks
One rule sits above the mode and wins every time. If the file changed on disk and you have unsaved edits in that tab, you are prompted — even in Auto-Reload, even in Never. A conflict trumps the mode. The wording differs so you can tell the two situations apart:
- With unsaved edits: "«X» changed on disk while you have unsaved edits."
- With nothing unsaved: "«X» was modified outside the app."
Both offer Reload and Keep My Version. Keep My Version makes your copy the one that counts: the tab is marked as changed, our auto-recovery safety net takes care of it straight away, and it survives a relaunch. Nothing on disk is touched until you save.
One more case ignores the mode. If another tool replaces the file wholesale — deleting it and putting a new one in its place — you are always asked before the replacement is taken. And you are never interrupted over a change that leaves the text alone: adjusting a file's permissions, on its own, produces no prompt at all.
Logs reload themselves, and the rule is exact
In Ask mode there is one exception that keeps logs usable. If the file looks like a log, the log setting is on, and you have no unsaved edits in that tab, the change is taken silently instead of prompting.
"Looks like a log" means the extension is .log or .out, so the files a build or a service writes keep themselves current while a document you are working on is never reloaded out from under you. For anything else that grows while you watch it — a build transcript, a capture, a file with no extension at all — set that tab to Auto-Reload and turn on View ▸ Follow Tail, and you have the same live view whatever the file is called.
Silent reloading and following a growing file are separate things: a reload brings the tab up to date with everything on disk, while following keeps you at the end of the file as it grows. For a file still being written to, choose View ▸ Follow Tail, which pins the tab to the end so new lines appear underneath the last ones as they are written.
Follow Tail is set per tab, so one tab can stay pinned to a running log while you read and type freely in every other tab beside it. Scrolling up releases the pin so you can read; scrolling to the bottom picks it up again. New lines are not treated as edits of yours, so undo still steps back through your own typing and nothing else. When a log rotates and the file starts over from nothing, the tab starts again from the top. Our large-file engine keeps the tab responsive however long the log runs.
What to expect on a network volume
A file on your own disk behaves the way you would hope: a change written by a script or a build reaches the tab promptly, and the interval in Settings rarely matters. A file on a mounted share is the case worth thinking about: a change made on another machine can take a little longer to reach you, and the interval in Settings is the control that decides how much longer.
If you are only reading such a file — a report on a server, a log on a build machine — shorten the interval and set the mode to Auto-Reload. The tab then keeps itself current.
If someone else might be editing the same file, do the opposite. Leave the mode on Ask and the warn-on-unsaved setting on, and let the prompt catch the collision. That is the one case where being interrupted is the point.
Your own saves do not count as external changes
Pressing ⌘S never comes back at you as a question about whether you would like to reload what you just wrote. Save as often as you like; your own saves are never reported as somebody else's work.
The distinction matters. Formatters, linters and build scripts often rewrite a file a moment after you save it, and when that happens you are told, because the rewrite did not come from you. Reload to take its version, or Keep My Version to hold on to yours.
Prompts on tabs you are not looking at
A change to a background tab does not throw a sheet over whatever you are doing. The tab gets an orange dot and the prompt is held until you switch to it.
When you switch to the tab, the question reflects the file as it stands at that moment. If the difference resolved itself while you were elsewhere, no sheet appears at all. You are asked once per tab however many times the file changed in the meantime, so coming back after an hour of churn gets you one question, not sixty.
The orange dot on a tab means "changed on disk". It is not an unsaved-changes marker. Unsaved work is shown by a leading asterisk on the tab title.
Scratch notes are held safe too
Watching is about files that live at a path on disk, so an untitled tab — the one you opened to paste a snippet into, or to think out loud in — is covered by our auto-recovery safety net instead. Type into it, quit without ever choosing a name or a folder, come back tomorrow, and the text is waiting for you as you left it. The same protection carries the recovery tabs that reopen after an unclean exit: they arrive already safe, with your text where you left it. The badge at the bottom of the window is there for the files being followed on disk, where the state is something you might want to act on; a scratch tab simply keeps what you typed.
It means the two halves of a session are each covered by the thing that suits them. Files on disk get the modes above, so you always know whether what you are reading is current. Everything you have not saved anywhere yet gets held for you regardless, on your Mac, with no account and nothing uploaded.
Deletion
Deletion detection is on by default and is separate from the change mode. If a watched file disappears you are told once — "«X» was deleted from disk." — and offered Keep in Editor or Close Tab. Keeping it holds your text as the surviving copy, and nothing is written back until you save. If a file reappears at the same path, you are asked before the new one is taken. Turn deletion detection off in Settings ▸ File Monitor if your workflow generates a lot of transient files.
Four setups worth copying
The three modes, the interval and Follow Tail combine into a small number of arrangements that cover most of what people actually do with a file something else keeps rewriting. Each one is two decisions, and both of them are reachable from the badge menu at the bottom of the window or from Settings ▸ File Monitor.
| What you are doing | What to set |
|---|---|
| Reading a report a script regenerates | Auto-Reload, default interval. The tab is current every time you glance at it. |
| Watching a log that is still being written | Auto-Reload plus View ▸ Follow Tail, so new lines land underneath the last ones as they arrive. |
| Editing a file a colleague also has open | Ask, warn-on-unsaved left on, a shorter interval. The prompt catches the collision while it still matters. |
| Holding a reference copy still while you work | Never. The text stays exactly as you found it until you press ⌘R yourself. |
Whichever you pick, the sheet always offers the same two answers and both of them are safe: Reload takes the version on disk, Keep My Version keeps yours, and nothing on disk is written until you save. One decision, and you are free to answer it the other way at the next prompt.
Monitoring is decided per open document, which is what makes the table above work. One tab can sit on Auto-Reload keeping up with a build while the file beside it stays on Ask because you are typing into it, and a third holds still on Never. The badge tells you which of them you are looking at, so the state of the text in front of you is something you can read off the window rather than something you have to remember.
⌘R sits underneath all four as the manual override. It reloads the tab in front of you once, from File ▸ Reload from Disk, without touching a single setting — useful when you have Never or Ask in place for good reasons and simply want this one file brought up to date this one time.
Troubleshooting
I turned monitoring on and nothing is being watched
Tabs that were already open when you flipped the switch stay unwatched. Close them and open them again. This is the single most common reason changes go unnoticed after a settings change.
It keeps asking even though I chose Auto-Reload
You have unsaved edits in that tab. Unsaved work wins over the mode — silently discarding your typing would be the wrong answer at any setting — so the change waits at a prompt and you say what happens to it. Answer Keep My Version to hold on to your copy, or Reload to take the one on disk. Save the tab with ⌘S and the conflict is settled: with nothing of yours in the balance, Auto-Reload goes back to taking each change as it arrives, silently. On a tab you only ever read from, that is the steady state from the start, and the prompt never appears at all.
Changes on a network volume take too long to appear
A change written on another machine can take a little longer to reach you than one written on your own disk. Shorten the interval in Settings ▸ File Monitor; the range is 1 to 600 seconds.
My log file is not reloading by itself
Check the extension: .log and .out are the two that reload themselves silently, and a file saved under either name gets that behaviour from the moment you open it. Check the tab for unsaved edits as well — once you have typed into a file your version comes first, so the change waits at a prompt and you decide what happens to it. To keep up with a file that is still being appended to, Follow Tail is the better tool either way: set that tab to Auto-Reload, turn it on from View ▸ Follow Tail, and new lines land underneath the last ones whatever the file is called.
The reload did not happen and the text is unchanged
If the file could not be read at that moment — locked, mid-write, or its permissions changed — the tab is left exactly as it was, with your text intact; you never end up looking at a partial or empty version of it. Try ⌘R for File ▸ Reload from Disk once the file settles. That is also the answer when you want to reload once without changing any setting.
Frequently asked questions
What is the difference between Never and turning monitoring off?
Never keeps the file watched but does nothing when its contents change: what is in the tab stays put until you reload it yourself with ⌘R. Deletion is still reported. Turning monitoring off stops the watching altogether, and every file you open from that point on follows whichever setting is in place at the time.
Will auto-reload ever throw away my unsaved work?
Your unsaved work comes first, and with warn-on-unsaved left on — which is the default — it stays that way. A change arriving while the tab has unsaved edits always prompts, whatever the mode says, and Keep My Version hands your copy straight to our auto-recovery safety net so it is still there after a relaunch. That copy stays on your Mac: nothing is uploaded and there is no account.
Does Note My notice a change if the file is on a network share?
Yes. Expect a change made on another machine to arrive a little behind one made on your own disk. The default interval is 3 seconds, adjustable between 1 and 600, so you can have the answer sooner.
Why does my own save not trigger a reload prompt?
Because your own save is not an external change, and ⌘S never turns into a question about work you have just done. A rewrite that arrives from somewhere else — a formatter or a build step tidying the file up behind you — is reported, and you choose Reload or Keep My Version.
What happens if the file is deleted while I have it open?
You are told once and offered Keep in Editor or Close Tab. Keeping it makes your copy the surviving one, protected like any unsaved work. Deletion detection can be turned off in Settings ▸ File Monitor.