Error in build

You can explicitly set up the location where you'd like it to find your cygwin, and consequently make install. Try the following:

- From Window menu, select Preferences

- In Preferences select Nios II Tool Locations

- On that page, find the section labelled 'Cygwin Tools Location (such as make, find, rm)

- Even if it looks like it is pointing to the correct cygwin, select the radio option that says 'Specify the Cygwin tools directory'

- Enter the valid path to the cygwin tools install e.g. d:\quartus\bin\cygwin\bin

- Hit Apply Button

- Hit OK

Try to build again