ACL Crash: How to Decide Between Working Copy and Last Saved

An ACL project crashing can be a disappointing moment for any ACL user. Here is a summary of what you will see and some helpful tips to take into consideration when determining which option will be best in your situation. We’ll also show you how to make a copy so you can keep both versions in case you accidentally make the wrong choice.

The Options

When you go to reopen the project you are left with two options: Working Copy or Last-Saved version.


The working copy is a .AC file that is automatically created by ACL for every project and serves as a temporary auto-save file. All unsaved changes to the ACL project are recorded here so that the changes can be recovered if ACL closes unexpectedly.

The last-saved version is the .ACL file, and contains the project at the point in time that you last saved.

WARNING!!! By selecting the working copy, ACL will automatically overwrite the last saved version as soon as it is opened.

Deciding Factors

1-     How large is the project file?

2-     When was the file last modified?

3-     What were you doing?

First, review the file size and last modified date/time. To do this, find where your ACL project is located on your computer/network drive. Sort your folder by Type (so the .AC and .ACL files appear at the top) and compare the file size and modified date/time between the .ACL file (last-saved) and the .AC file (working copy).

June 2

  • Factor 1- File Size

Usually, a larger file size indicates that there is more content in the project. However, the data may be bad if it didn’t complete the analysis/command that ACL was in the middle of processing when it crashed. Depending on what you were doing (see below), it will not always be obvious that the analysis/command was mid-process when the project crashed. In addition, ACL frequently creates large temporary files to execute a command. These files will impact the size of the project, but may not be critical to your results. Temporary files may be misleading if you are relying on the file size to determine which option to select.

  • Factor 2- Last Modified Date/Time

If you know the last time/date you added or modified something that you need, you may want to consider this factor more heavily than the project size when choosing which file to open.

  • Factor 3- What was ACL Doing?

After comparing the file size and last modified date, determine what you were in the middle of doing when ACL crashed. Knowing what ACL was doing when it crashed is likely to be the most critical factor to determining which option to pick.

A few examples of things that you may have been doing are listed below. If none of the options below describe what you were doing, skip ahead to the “When You Don’t Know” selection below.

Importing Data– The larger size file likely has more data, but may be incomplete… you may want to consider the modified time and go with the option that you know is correct/complete.

Performing Analysis with a Command-  This is a tough call. You may want to default to the “When you don’t know” selection below just to be safe.

Writing a Script-  Scripts typically do not significantly impact the file size. The most recent file may be your best bet.

Running an Analysis Script-  This is also a tough call. You may want to default to the “When You Don’t Know” selection below just to be safe.

Running a Clean-Up Script-  The smaller size file is likely the most up to date.

When You Don’t Know- Play it Safe

If you are not 100% sure which one to choose, you can always select cancel and create a copy of both files and save it as a different name. If you discover that the selected copy is not what you want, simply close the project and open the re-named copy that you created. If necessary, you can change the file extension from .AC to .ACL to open your re-named copy.