MacMost Now 717: The Library Folders

While you may never need to go into your Mac's Library folders, it can be enlightening to know what they are used for and what is inside. This is where things like fonts, caches, preferences files and application support files are stored.
Video Transcript / Captions
Closed captioning for this video is available on YouTube: MacMost Now 717: The Library Folders.

Hi, this is Gary with MacMost Now. On today's episode let's take look inside your Library Folder.

Now in your home folder you've got all your documents. You've got your movies, photos, music. You have all the files you need to get to. Up above your User folder you've got things like the System folder and the Library folder. The library folder contains all these different files that you are accessing every day but you might not even know it. Things like "fonts", things like "cache files" for your browser, things like "preference files" for different applications. Let's go take a look inside the Library folder just so you know more about how your computer works.

So here I am looking in the Finder window. I am using the column view so I can easily see where things are. I am in my home folder and I can see there's my documents and movies and music. Now there is also a library folder here but we can't see it. It is kind of hidden from us and this is just a general hint that we should not be messing with the files in there but you can still get to it. The easiest way to get to it is to use the "Go" menu where you still don't see the library folder. But if I hold down the option key it appears and I can let go. Now you can see that it has shifted over and is now a visible folder and I can look at the files and folders in it.

Now you are going to see tons of different folders in here. It is going to be different than what I see because the contents of the Library folder depend upon what type of Mac you have, what types of applications, utilities and things that you have installed on your system. Some of these things will be the same and some will be different. For instance, you most likely have a Fonts folder here and inside of it you would have any custom fonts for this user. Notice I have none for this user, I just have the standard Mac fonts here. In addition, you will have a Preferences folder. Inside of that are the preferences for all the different applications you have. Even if you don't think of an application as having preferences it does have a few settings so it will remember those and put them in files like com.and the name of the company and the name of the application. For instance, here is the activity monitor preferences which is com.Apple.activitymonitor.plist. Sometimes it will be in folders, like for instance here are the photoshop settings and that's in a folder there and you can find all sorts of different things here. For instance if I scroll down I can find Final Cut and there's Microsoft Office 2011. So you can find all your different preference files here. The only time this is useful is if an application is particularly misbehaving and just isn't working any more and you don't mind loosing preferences you can sometimes go in and find the preference file and throw it away and then you run the application. It is like running it for the first time and sometimes it can clear out problems.

Now another very important folder in the Library folder is the Application Support folder. Now this is where a lot of different things are thrown in. For instance if you have a streaming music app it has to store all that music and it's not going to store it as documents. It is going to put it in the application support folder in the sub folder for it. So there are all sorts of different things we can get. We can get extensions for different applications, we can get new content for different applications. For instance if you look in GarageBand there is the instrument library. If I look under Microsoft I can see Microsoft Silverlight and that is where that is stored. So any time you add something to an application and it is not going to alter the application file, that will remain the same, but it will put those things inside the application support folder.

Now also in Application Support you will also find caches. Caches are temporary files. For instance, the most common type of cache is Web Browser cache where it will store a web page so if you go back to it again immediately it doesn't have to fetch it again from the internet. But most of those are stored under caches in the caches folder here and you can see things sorted by application. For instance if I can go down here and find the Safari cache where all the pages that I have recently visited are temporarily cached. It is amazing how many applications have caches, even ones you don't think of as having something to cache will put little things. For instance, iMovie will put little thumbnails and bits in there so it doesn't have to recreate those.

I mentioned before that if you look here this is the Library folder that is inside of my home folder called MacMost. Now there are two Library folders that you have to deal with. This one is for the specific user, MacMost. Now the Mac can have more than one user. There is a Library folder at the system level. If I go up here above Users to Macintosh HD I can see the System folder and Users, and there is a Library folder there too. You see a lot of the same things here. You can see Application Support, and you find Preferences here. This is where things will be stored that have to do with ALL the users rather than just that single user there. So, you will find a lot of different things. For instance, fonts. Here you can find all the fonts that are I have got on this machine because as I have installed fonts there is the original ones and the ones I have installed. I have set it so these fonts are available for all users on the machine. They are going to be installed at the top level Library folder not in the MacMost Library folder because then I can switch to a different user and it wouldn't be available to that user.

So when looking into your Library folder keep in mind that you have two Library folders and if it is something for the entire computer it's in the main one and if it is just something for that one user it is in the user's Library folder.

In general, for most users, you should not have to look in the Library folder. Things like Preferences and caches and all that can be dealt with inside the individual applications. For instance, if I wanted to clear the Safari cache I can do that using the the Safari Preferences. If I wanted to set a specific Preference I should be able to do that inside the Preferences for that App. If I wanted to add a Font I would do it using the Font book utility. So there is no real reason for the typical Mac user to ever go inside the Library folder; but sometimes it is useful to know it's there and to know what it is used for.

I hope you found this useful. Until next time this is Gary with MacMost Now.

Comments: 5 Responses to “MacMost Now 717: The Library Folders”

    Jerry G
    7 years ago

    Hi Gary,

    One fairly common reason to access the User’s Library is to delete a no longer needed Custom iWork Template. Since the User’s Library became hidden in Lion, some iWork users have been disoriented since they were used to going there to manage their templates. Your great explanation should help with that.


    Bev Mascara
    7 years ago

    Thank you for this…very clear, consice and helpful.

    Michael Dunlop
    7 years ago

    Another helpful, concise mini tutorial.
    I enjoy all you videos and they have certainly revealed some most interesting tips and guides to making the most of Mac power!
    Thank you.

    Johnny Robish
    7 years ago

    I use the “Library” folder quite a bit to transfer my Mac Mail folder back and forth between my iMac and MacBook Pro. I use IMAP e-mail, which should make this step unnecessary, but I have two e-mail addresses which folders that contain e-mails from both under “on my Mac.”

    Patrick Green
    7 years ago

    My mac will not reveal the library when I hold down the option key (6:13). ?

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