microsoft excel - Conditional Formatting not working with formula

I'm using the below formula to input the name of my excel sheet into a cell. When i try to use conditional formatting on that cell and use the option "use a formula to determine which cells to format" to format the cell the data does not change.

=MID(CELL("filename",A1),FIND("]",CELL("filename",A1))+1,255)

I'm trying to get my sheet name (which is a date written as 010117) to display as 01/01/17. Since excel wont allow me to use the "/" symbol in the sheet name conditional formatting appears to be my only option but it doesn't work in this instance.

Options?