When you create a new Excel file and, before saving it, rename a worksheet to a name starting with "Delta(" or certain other function names, Excel 2013 crashes. When you save the file before renaming the worksheet, the problem does initially not occur. However, when you open such a file while think-cell is active, Excel 2013 crashes.
Excel 2013 also crashes if you create a reference to an existing worksheet whose name Excel 2013 recognizes as a function name from Microsoft's Analysis ToolPak (ATP).
This is caused by a bug in Excel 2013. The problem can be reproduced without think-cell by creating a new file and, before saving it, renaming the worksheet to "Delta(…".
Microsoft has fixed this problem. Please install KB2881085 from the "Office updates: July 8, 2014" or hotfix KB2882992 from the "Office 2013 cumulative update for July 2014". KB2881085 is installed automatically if you receive Office updates via Windows Update. The hotfix KB2882992 requires manual installation.