Your Logic Project is saved as a computer file on a storage device, and like with any file, things could go wrong and such a file could get corrupted. If that happens to your Logic Project File, then Logic might crash, every time you try to open it.

In the following article I show how to open a corrupted Logic Project, and more importantly, what you can do to be prepared for such an unfortunate situation that hopefully will never happen to you.

Anatomy of a Logic Project File

In order to understand how to fix a corrupted file or how to be prepared, you have to know a little bit about the "inside" of a Logic Project File.

Package Contents

Starting with Logic Pro X, a Project File is now a Package File type (sometimes also referred to as a Bundle). It looks like a regular file, but it is basically a folder in disguise. The reason for the "hiding" is to prevent the user from opening the folder and mess with the files inside, because Logic organizes those files in a specific way and relies on that structure. So let''s look at that structure:

• In the Finder, ctrl-click on a Logic Project File. This will open a Shortcut Menu with the command "Show Package Contents" ➊. This is the key to "open up" that file, in this case "open that folder". Because you cannot see on the outside if a file on the Finder is a Package File, this is a way to find out. Only Package Files display that command ➊.

1st Level - Top Level

When you save a new Logic Project and open that file right away with the Show Package Contents ➊ command, you can see three folders ➋. As you continue to work on your Project, Logic might add additional folders to it. For now, we are only interested in one folder "Alternatives" ➌.

2nd Level - Alternatives

When you open the Alternatives folder, you will see one folder inside, named "000" ➍. To understand that folder, let me quickly review some basic concepts in LPX:

• In Logic Pro 9, when you wanted to work on a different version of the same Project, for example, to create an alternate mix, you saved your Project as a separate Project File. When working on another version of your Project, you save it again as yet another separate Project File.
• Now in LPX, you can stay in the same Project and save those alternative versions as so-called "Alternatives", stored inside the same Project File. Even when you first start with a new Project, that single Project is internally also considered an Alternative, the default Alternative
• The concept of Alternatives allows you to switch between those Alternatives without leaving the currently active Project. This way, you don''t have to track separate Project Files. In addition, all those Alternatives use the same Media Files, so you don''t duplicate asset files unnecessarily.
• The management of those Alternatives is done in Logic''s Main Menu File ➤ Alternatives ➤ ➎. If you don''t need that feature and always work with a single Project, then you don''t have to bother about that menu at all. It just lists the name of your Project, the default Alternative Project if you will.
• Logic stores the individual data for each Alternative in their own separate folders ➏ inside the the"Alternatives" folder. Each folder represents one Alternative, named sequentially "000" (the default Project), "001", 002", and so on.
• Here is an example, where I have four Projects (four Alternatives listed in the Alternatives submenu ➐) and on the Finder you would see four corresponding folders inside the Alternatives folder ➏. You just have to get used to that your default Project is considered an Alternative, "Alternative 000".

3rd Level - 000, 001, etc.

• ProjectData ➋: This is the core of your Project (that specific Alternative). The file stores everything about that Alternative (except the actual media files), for example, Regions, MIDI, Events, Automation, etc. When you open a Project, Logic reads the content of that file, and if that file gets corrupted, then you are hosed and Logic will crash.
• Autosave ➌: This is the folder were Logic records every edit you make from the moment you used the Save command until the next time you use the Save command again. This is your golden parachute that lets you get your Project back after a crash, with all the edits you made after the last time you''ve saved your Project.
• Project File Backups ➍: This is the folder were Logic saves the different backups of you Project. The feature is called "Auto Backup" and users often confuse it with "Autosave". I provide in-depth explanations about the procedure of those different features in my book "Logic Pro X - How it Works". Every time you use the Save command in your Project, Logic will copy the current Project data to that Project File Backups folder ➍ before saving (overwriting) the actual Project. In the Preferences ➤ General ➤ Project Handling ➤ Auto Backup menu ➎, you set how many backup versions Logic should keep (0 … 100).

4th Level - Project File Backup

Let's drill down another level and open that "Project File Backups" folder. ➏ Here is what you have to know about it:

• The Project File Backups folder contains additional folders ➐ named "00", "01", "02", etc., where each folder contains the data for a specific Backup.
• Every time you use Logic''s Save command, the next folder is created and Logic copies over the ProjectData file ➑ from the parent folder before it overwrites it with the new changes.
• Once you reached the maximum numbers of backups (set in the preferences ➎), which means the maximum amount of folders, Logic will overwrite the data in the first folder (00), then the second folder (01), and so on.
• In the Logic Main Menu File ➤ Revert to ➤ ➒ all those Backups are listed with a time stamp. Each item represents an individual folder ➓ (00, 01, 02, etc.) in the Project File Backups folder ➏, and selecting an item from the menu ➓, will load that ProjectData file ➑ from its corresponding folder, changing the Project to that specific version.
• On a side note: While Logic Pro 9 saved Backups as individual Projects that you could open from the Finder, the Project Backups in LPX are saved inside the Project File, which have to be opened from inside Logic. However, there is a way to open those individual backups directly from the Finder, as we will see in the next section.

How to Fix It

Now with that deeper understanding of the Logic Project File, let''s find out how to fix it if it gets corrupted.

The file that most likely gets corrupted is not the actual Logic Project File, because we know that this is a folder and not the file. Instead, it is the file that holds all the information about your Project, which is the "ProjectData" file. But there is not just one ProjectData file inside your Logic Project File.

• Each Alternative folder (000, 001, 002, etc.) has its own ProjectData file
• Each Backup folder (00, 01, 002, etc.) inside each Alternative also has its own ProjectData file.

So which of those files causes the crash? When you open a Project File, Logic will always open the Alternative that was open the last time you saved the Project. If the ProjectData file of that Alternative got corrupted, then it crashes every time you try to open it. So how do you avoid that?

The trick is to open the Logic Project, but not the version that was last open. Here are three options:

• Different Backup Project: You have to tell Logic to open one of the Backup versions, preferably the last one.
• Different Alternative: You have to tell Logic to open a different Alternative.
• Replace ProjectData: You have to replace the actual corrupted ProjectData file with a non-corrupted one.

Solution 1

Logic has a clever mechanism that opens a special window called "Select Alternative and Backup" ➊. Instead of directly open the Project (and facing the crash), Logic will show you this window first and lets you choose a specific Alternative ➋, or a specific Backup version ➌ of any of the Alternatives. There are different procedures to get to that window from inside Logic or even from the Finder without having to have Logic open first.

From inside Logic

Open Logic with a new Project or any existing Project and use one of the following commands to prompt the special "Select Alternative and Backup" window:

• Use the Menu Command File ➤ Open… to open the Open Dialog.  Now, hold down the option key when either double-clicking on a file, using the Open button, or using the return key to launch a Project.
• In Logic, hold down the option key when selecting a Project from the Main Menu File ➤ Open Recent ➤
  

From the Finder

You can get to the "Select Alternative and Backup" window without having Logic to be launched first.

• Launch File: In the Finder, hold down the option key when double-clicking on a Logic Project File.
• Launch Logic: Hold down the option key when launching the Logic app (only when you have the Preferences ➤ General ➤ Project Handling ➤ Startup Action set to "Launch Default Template").

From Quick Look

Quick Look is a powerful, but often overlooked OSX feature that lets you preview a wide variety of files in the Finder with a Quick Look Window without launching first its required app. This also works for Logic Project Files. The Quick Look Window ➍ displays the WindowImage, which is a screenshot ➎ of the active Logic window when you saved the Project. Besides some other useful features, it lists on the right side ➏ all the Alternatives in that Project, so you can open a Project directly with a specific Alternative. When you click on "Load a Backup", that special "Select Alternative and Backup" ➐ window will open to launch a specific Backup version of the Project.

Here are different ways how to access Quick Look:

• In the Finder, select the Project File ➑ and hit the spacebar or cmd+Y to toggle the Quick Look Window.
• Select the Project File ➑, click the Action Button ➒ in the Finder Toolbar, and select the "Quick Look NameOfTheFile.logicx" ➓ command. Once the window is open, the command changes to "Close Quick Lock" to do exactly that.
• Ctr+click the Project File ➑ and select the "Quick Look NameOfTheFile.logicx" ➓ command from the Shortcut Menu. Once the window is open, the command changes to "Close Quick Lock".

Solution 2

This solution is a more "surgical" procedure where you operate inside the Project File. So please know what you are doing.

In this example, lets assume that you had Alternative "000" ➊ open the last time, and that is where the corrupt ProjectData is located.

• First, quit Logic before doing anything.
• Also, make a backup copy of the damaged Project File.
• Now, trash that corrupted ProjectData file ➋ inside the Alternatives folder "000", or you can move it to to the Desktop.
• In the Project File Backups folder locate the folder with the most recent modification date (your most recent backup of that Alternative). In this example, it is folder "00" ➌.
• Copy the ProjectData file ➍ from the folder Project File Backups ➤ 00 to the folder "000".

What you''ve Achieved

• You put the ProjectData file ➎ of the last backup of your Project (folder "00" ➌) into the main folder of that Alternative ➊ so it becomes the current Project.
• Now when you launch that Project, Logic sees a proper (non-corrupted) ProjectData file and launches without crashing (hopefully).
• The only drawback is that you lost the edits that you made since the last backup of that Alternative, but at least you didn''t lose the entire Project.

Other Considerations

• The other two files ➏ in the "000" folder are automatically overwritten when you save the next time and don''t need to be replaced manually. DisplayState.plist just stores the current window placements and the WindowImage.jpg file stores a screenshot of the currently active window.
• The Autosave folder ➐ contains files that represent the most recent "autosaved" state of your Project. This might be another backdoor to get your Project back.

Preparation

To be better prepared for a corrupted file  situation, consider the following steps:

• Make sure you have the Auto Backup feature enabled in Logic so you have those backup files available when needed.
• Saving an Alternative once in a while just to use as an additional backup "fallback" is also an option, depending on your paranoia level, I mean, safety concerns.
• Running TimeMachine is also a good idea, because it automatically makes incremental backups every hour (if that doesn''t interfere with your production).

If you want to practice the procedure

You don''t have to wait until disaster strikes to test the procedures I explained. On a test Project, open the ProjectData file in a text editor, select a few lines of text and delete them. Save it and you have yourself a corrupted Project. Now apply the procedures.

Graphically Enhanced Manuals

I hope you found this tutorial useful. If you are interested in learning more about Logic Pro X, check out my books "Logic Pro X - How it Works", "Logic Pro X - The Details", "Logic Pro X - Tips, Tricks, Secrets #1", and "Logic Pro X - Tips, Tricks, Secrets #2". They are available as pdf, printed books on Amazon and interactive multi-touch iBooks on Apple''s iBooks Store.

For a list of all my books in my "Graphically Enhanced Manuals (GEM)" series and all the links, go to my website.

http://DingDingMusic.com/GEM/