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Which version to install depends on which version of MacOS you have. For OSX 10.7.5 and up we currently recommend the most recent stable release which may be downloaded from .

For older Macs version 3.5.25 should work which can be found here .

If you have difficulty with the version you downloaded and you're on OSX 10.7.5 or higher, then try the latest beta release from . For older versions of OSX there is no readily available alternative. 

After installing tunnelblick, download the config file. The configuration file is compressed, so double-click it to expand it: you should then get a file 'chemistry.tblk'. ('chemistry.tblk' will not run from the Downloads folder. Copy to the Desktop). Double-click 'chemistry.tblk' to install the configuration.


Select 'Connect Chemistry' from the TunnelBlick icon. The credentials you should use are your ChemNet credentials. These can be collected from and it is OK to tell Tunnelblick to save them. If you are using Chrome as your web browser please type the credentials in, do not cut and paste as this has been proved not to work. Please note that the ChemNet username is your CRSID followed by , not . 

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