The reason being is that you have not specificied the folder location thus it is storing it in your default location i.e My documents.

What you need to do is specify the full address like "c:/My Documents/Testing folder/" & Thisfile etc.

Try this

Sub SaveAsMaximoWO()
dim ThisFile as string
dim thisfile2 as string
Dim WorkPath as string

ThisFile = Range("AC5").Value '
ThisFile2 = Range("E3").Value ' not sure if it already has the .xls extension so will add it into the string
WorkPath = thisworkbook.path & "/Save Folder"

saveName = WorkPath & '/' & ThisFile " - " & ThisFile2 & ".xls"
ActiveWorkbook.SaveAs Filename:=saveName

End Sub

so in this case what should happen is that say the activeworkbook is in My documents then it would save it in My documents under the subfolder called "Save Folder". Just make sure that the subfolder exists else it will crash.