Why am I unable to connect signals to Altera components in Qsys?

Description

You may see this behavior when the environment variable is set in your enviroment and SOPC Builder has been launched before you launch Qsys.

Resolution

To correct this behavior, follow the steps below:

1. Unset the enviroment variable .
2. Delete the directory .altera.quartus/ip in your user directory.
• For Linux systems, ~/.
• For Windows, C:\Documents and Settings\<user name> or C:\Users\<user name>

The variable is deprecated for the Quartus II software version 9.0 or later.