My first response is as useful as your post of the problem. It tells you nothing.
If you want a better answer you need to give more information. What kind of problem are you having?
Is the Project Tool failing? If so, what error message do you see?
Is it creating an output in the wrong place? What does that look like (i.e., provide a screen shot)?
Describe the data you are trying to project. Provide the operating system of your home PC and your work PC. What steps are you following to Project your data?
Here is the change log for version 10.3. It will list 10.2.x bugs that were fixed during the upgrade.
You will have to go through it to see what changes were made
a running set of changes and information about arcgis and associated software is maintained on my blog here