The problem was solved by getting an new license . dat from my seller.

Berthold Heinrich

@Mac Dude 

I checked the files. License. dat is there, soap.dat not. But in Maple 18 I never had such a file (even not in all my backups).

Reinstall doesn't work because I have the license for only one installation.

Thanks

Berthold

@Mac Dude 

I did nothing. ;-)

After updating to OS X Yosemite I wanted to start my Maple (baught about 9 month ago for OS X Mavericks).

The follwing Error Windows occurs

Maple Initialization Error

Invald or missing license file.

The histid ...

I can chose "Quit", "Web Store" or "Activate".

If I choose "Activate" I can type my SN, but the same Error Window occurs.

Yours

Berthold Heinrich