Using a combination of posted answers, here is the solution I came up with:
My environment:
- rbenv
- rails 4.1.8
- i18n (0.7.0.beta1)
My problem: After running gem install mailcatcher in my existing rails project folder, I started mailcatcher and got:
`require ': cannot load such file - i18n / core_ext / string / interpolate (LoadError)
I did not want to mess with updating the i18n gem in my existing project folder, since everything in my project worked fine.
Taking the @joostvanrijn advice, I decide to create a separate rails project folder specifically for MailCatcher. I named the mailcatcher folder. In my newly created /mailcatcher folder, I ran gem install mailcatcher . Then I launched gem update i18n , which led me to i18n-0.7.0 . Finally, I called mailcatcher and it ran without difficulty.
Later I ran into another problem with MailCatcher:
While I could get to http://127.0.0.1:1080 , sending email with an error
500 internal server errors completed
Net :: ReadTimeout (Net :: ReadTimeout)
I tried to exit MailCatcher by going to http://127.0.0.1:1080 and pressing "Quit", but that would just lead me to http://mailcatcher.me and not actually kill the process.
To kill the process, I used lsof -i -n -P | grep TCP lsof -i -n -P | grep TCP to find processes running on 127.0.0.1:1025 and 127.0.0.1:1080 , and used kill -9 PID .
I learned from this post discourse that Net::ReadTimeout caused by an error in MailCatcher, and a workaround is to run MailCatcher in the foreground using mailcatcher -f . This solved my problem, and now I can "catch" emails without any problems. Hooray!