With the 2015 release of Illustrator CC, you can recover your work if Illustrator crashes and you have forgotten to save.

Illustrator CC can help you determine the cause of a crash, prevent the problem item from loading with Illustrator, and provide a list of problem-causing items so that you can troubleshoot them.

You can also decide how often your data is recovered and where your recovered data is stored. 

After a crash, relaunch Illustrator. In the dialog box that appears, click OK to close the dialog box or More Info to learn more.

Your recovered file has [Recovered] inserted after the filename. Choose File > Save As... to save your file. The Save As command lets you save the recovered file with a different version name until you are certain the recovered file contains the correct data. 

If a crash is due to an incompatible or out-of-date driver or plug-in, or a corrupt font, Illustrator gives you the option to diagnose the cause on relaunch.

In the dialog box that appears after relaunch, click Run Diagnostics to start the diagnostic tests.

Note: This step is repeated for each crash-inducing file that Illustrator finds. 

Once you choose Run Diagnostics (in the previous step), Illustrator launches in Safe Mode. In the Safe Mode dialog box, Illustrator lists the possible items causing the problems such as corrupt fonts, plug-ins, or out-of-date drivers.

Click on an item in the list. Check the troubleshooting tips for that item. Follow those tips to correct the problem. If you believe the problem item has been fixed, select the Enabled when Illustrator is relaunched check box for the item, then click Enable on Relaunch at the bottom of the dialog box.

Note: Illustrator continues to work in Safe Mode until all problems in the list have been fixed. Once all problems have been fixed, Illustrator launches in Normal Mode.

The Safe Mode link is only available when Illustrator is launched in Safe Mode.

If you close the Safe Mode dialog box to continue work before fixing and relaunching Illustrator, you can bring up the Safe Mode dialog box by clicking on Safe Mode in the Application bar. 

Illustrator lets you choose how often your recovery data is saved and where the data is stored.

From the Preferences menu, choose File Handling & Clipboard. Under Data Recovery, choose Automatically Save Recovery Data Every: and choose the time interval from the drop-down menu.

Note: Data Recovery is not absolute. There could be a loss of data if a crash happens between recovery intervals.

For very large, complex documents, Illustrator may pause to perform data recovery. In these cases, you may choose Turn off Data Recovery to prevent your workflow from being interrupted.