Anyone who has poured years into an app before knows how this goes. The company pivots, the pricing changes, the sync server quietly stops getting maintained, and one day you are staring at an export button that no longer works. So it is a fair question to ask before you put five years of images and links into Muse: where does any of this actually live, and what happens if the app is gone tomorrow.
The short version is that Muse's library is a folder on your Mac. Not a database behind a login, not a cache of some account in the cloud. A folder, with files inside it, that you can open in Finder right now. Here is exactly what is in it, how backup already covers it, and how you get everything back out.
Where does Muse actually keep your library?
By default, everything you save into Muse lands in a folder called Muse Library, inside Pictures on your Mac. Open Finder, go to Pictures, and it is right there. Inside is a small database file that holds the organising information, titles, tags, notes and which collections things belong to, plus a folder of the original files themselves: the images, screenshots and saved pages you have collected. There is also a thumbnail cache, which is disposable and rebuilds itself if it is ever deleted.
You can move the whole folder to a different drive from Settings if you would rather your library sat on an external disk than your internal one. Either way, it stays a folder you can see and open, not something locked inside an account that only Muse's own servers can reach. Parking that folder inside iCloud Drive rather than on local storage changes some of this, and what actually changes between iCloud Drive and local files is worth reading before you decide where the folder should live.
Muse copies your files in
Here is the part worth being straightforward about. When you save something to Muse, it does not leave the original where it was and simply remember the location. It makes a copy and stores that copy inside the Muse Library folder. This is the same approach Eagle takes, and most serious local library apps take it for the same reason: if Muse only pointed at files scattered across your Mac, moving, renaming or tidying up any one of them anywhere else would quietly break your library.
A library built from copies cannot be broken by cleaning out your Downloads folder six months later. That reliability is worth the disk space it costs, and Export My Library (below) means the copy never becomes a trap.
The trade-off is real, so it is worth naming rather than hiding. Your library uses extra disk space, roughly the size of everything you have collected, on top of any originals you kept elsewhere. What you get for it is a library that stays intact even if the file it came from is later renamed, moved or deleted from wherever you first captured it.
Does a normal Mac backup already cover it?
Yes, because it is not a special case. Muse Library is a folder like Documents or Desktop, so any backup tool that covers your whole Mac already covers it. Time Machine, if you have it turned on, is already copying it every time it runs. The same goes for Backblaze, Carbon Copy Cloner or anything else aimed at your disk as a whole. There is nothing Muse-specific to configure for that baseline protection, beyond checking your backup tool actually includes the Pictures folder. Apple's own guide to backing up with Time Machine covers the setup if you have not turned it on yet.
Muse also has its own backup feature, separate from whatever runs at the system level. Settings includes a Backup section where you can choose a destination folder, back up on demand, and set a daily or weekly schedule that keeps a chosen number of past snapshots rather than just the newest one. It is a second, independent copy, useful if you want a Muse-specific backup on a different drive from your main Time Machine target, or you simply want more than one point in time to fall back to.
Getting everything back out
This is the part that actually answers the "what if the app goes away" question, because a folder you can look at is not quite the same as a folder you can use somewhere else. Muse's Export My Library writes any collection back out as ordinary folders and files: images and other originals as themselves, saved links as files you can open, nested the way your collections are nested. Nothing about the result depends on having Muse installed to open it. For a closer look at what actually lands on disk, a full walkthrough of exporting a collection as folders checks the output against real files, folder by folder.
Use it whenever suits you, not only as an exit plan. Some people run an export before a big Mac migration just to have a plain-folder copy sitting on an external drive, sitting alongside the working library rather than replacing it.
What happens when the trial ends?
Muse is free to try for 30 days, no card needed to start. When the trial ends, the whole app locks, not just some features. You cannot capture new items, edit anything or reorganise a collection until you activate a licence. This is worth being precise about: it is not a read-only mode where browsing and search keep working while saving stops. The library itself sits untouched behind that lock. Buying a licence unlocks the exact same files; nothing is deleted or held back in the meantime.
Export is the one thing that keeps working through the lock. If you decide Muse is not for you, you are not stuck: Export My Library still writes your collections out as real folders after the trial ends, exactly as it would before. You are never locked out of your own files, even if you never pay for the app that organised them.
Put together, that is the honest answer to the trust question. Your files sit in a folder you already own, copied in rather than merely referenced, covered by whatever backup habits you already have, and always exportable in full, trial or no trial, licence or no licence.
Frequently asked
Where exactly is the Muse library stored on my Mac?
Does Muse copy my files or leave them where they were?
Will Time Machine back up my Muse library automatically?
Can I get my files out of Muse if I stop using it?
What happens to my library when the trial ends?
Your library, your folder, your call
Free for 30 days. Then $29 once, and it is yours.