IBM Cognos 10: DPR-ERR-2107

Problem
When starting IBM Cognos 10, before the login prompt, the following error appears:
DPR-ERR-2107
The User Capabilities Cache cookie cannot be decoded.


Solution
With two Cognos systems that you run one after the other, this error can occur. Close your browser in between running separate Congos'.

For example, if you have a production Cognos and a development Cognos, you run the development edition, then you open a new tab and run the production edition - it will give you this error. Close the browser completely, reopen it and try again, it will be fine.