A GAMS license is generated as a plain ASCII file of six lines, which has been sent to you via e-mail. Please make sure to copy all six lines into a file gamslice.txt. To activate the license please follow these steps:

• For MS Windows there are different options:
  • During the setup of the GAMS system you will be asked for the license file. Follow these instructions.
  • If you have already installed the GAMS system without a license file or want to replace an existing license file with a new one:
    • Copy the contents of the license file to your clipboard. Then open the GAMSIDE and navigate to: Help → About. The GAMSIDE will recognize the presence of the license in your clipboard and ask, whether you want to create a license. Note: An existing license file will be overwritten.
    • Or just copy the file as gamslice.txt into your GAMS System Directory.

• Unix: To activate the license please copy the license file as gamslice.txt into your GAMS System Directory (e.g. /usr/bin/gams).
• Wine: To activate the license please copy the license file as gamslice.txt into your WINE GAMS System Directory (e.g. $HOME/gams_wine). Alternatively, copy the contents of the license file to your clipboard, open the GAMSIDE and navigate to: Help → About.

For more information about the GAMS Installation please consult the GAMS Installation and System Notes for Windows, the GAMS Installation and System Notes for Unix or see video.

To display the current license file in the GAMSIDE goto Help → About. The model licememo from the GAMS Model library will provide extended information about the contents of the license file, see video.

When you run a model in GAMS the first lines in the log indicate the license you are using:

--- Job trnsport.gms Start 08/09/11 09:06:30 WEX-WEI 23.7.2 x86_64/MS Windows     
GAMS Rev 237  Copyright (C) 1987-2011 GAMS Development. All rights reserved
Licensee: Name of the User                               G070719/0001CB-WIN
          Name of the Institution                                    DCXXXX
--- Starting compilation
...

The output from a demo license reads:

--- Job trnsport.gms Start 08/09/11 09:07:26 WEX-WEI 23.7.2 x86_64/MS Windows     
GAMS Rev 237  Copyright (C) 1987-2011 GAMS Development. All rights reserved
Licensee: GAMS Development Corporation, Washington, DC   G871201/0000CA-ANY
          Free Demo,  202-342-0180,  sales@gams.com,  www.gams.com   DC0000
--- Starting compilation

If this happens after you copied gamslice.txt to the GAMS system directory please double check the name of the file (sometimes you will find a second extension like gamslice.txt.txt).

Do not try to modify the contents of the license file. The system will downgrade to the demonstration mode and issue an error message:

--- Job trnsport.gms Start 08/09/11 09:07:26 WEX-WEI 23.7.2 x86_64/MS Windows     
GAMS Rev 237  Copyright (C) 1987-2011 GAMS Development. All rights reserved
*** License File validation failed
*** System downgraded to demonstration mode

Please contact support@gams.com if this happens and attach your license file. More issues related to the license are discussed here.