Personal Macro Workbook interference with other workbook macro(s)

Have you declared any global variables? If so they may have values when the macro first runs.

Have you disabled events

Have you set manual calculation

Do you use "on error" to handle your errors?

'This code will ignore any errors

On Error resume next

So use this to select sheet1 for example
Check to see if the active sheet name is Sheet1
If not create Sheet1
But you must undo the error option as soon as possible

On Error goto 0

This Tells excel where to go if there is an error

On error goto ErrorSkip
Sheets("Sheet1").activate
Goto Skip

ErrorSkip:
'If you are here the Sheet1 does not exist so create it

Skip: 
' Ok at this point Sheet1 must exist
'So enable default error handling

On Error Goto 0

You could set a Global Variable

Dim ChangeFlag as Boolean

then check if the flag is set before running a macro

this will mean you control which macros are run

Public ChangeFlag as Boolean
sub Macro1()

If ChangeFlag = True then exit sub
ChangeFlag = True

'Run Macro2
Macro2
ChangeFlag = false
End sub


Sub Macro2()
If ChangeFlag = True then exit sub

'This will never run


End sub