# How to debug failure on start from InstantRails **URL:** \ **Category:** Rails\ **Created:** [July 12, 2007, 1:17am UTC](https://www.ruby-forum.com/t/how-to-debug-failure-on-start-from-instantrails/109164 "2007-07-12T01:17:58Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![lunaclaire](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/f4b2a3/32.png) [@lunaclaire](https://www.ruby-forum.com/u/lunaclaire)\ **Post date:** [July 12, 2007, 1:17am UTC](https://www.ruby-forum.com/t/how-to-debug-failure-on-start-from-instantrails/109164/1 "2007-07-12T01:17:58Z")
I made some change that I cant track down by looking at source code that prevents my app from starting when launching from InstantRails. The console window that InstantRails opens displays some info, but it closes the window before I can read any of it, so does anybody have a tip on how I can “freeze” that window to see what’s getting spit back? Alternatively, is there a log file that would give me some info on what’s failing? (I tried development.log but that only seems to have logged stuff from the last time I launched and ran successfully) TIA ---
**Author:** ![lunaclaire](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/f4b2a3/32.png) [@lunaclaire](https://www.ruby-forum.com/u/lunaclaire)\ **Post date:** [July 12, 2007, 3:45am UTC](https://www.ruby-forum.com/t/how-to-debug-failure-on-start-from-instantrails/109164/2 "2007-07-12T03:45:11Z")
Hi, lunaclaire wrote: > I made some change that I cant track down by looking > at source code that prevents my app from starting when > launching from InstantRails. It’s possible, but somewhat unlikely, that your problem is rooted in your code. > The console window that InstantRails opens displays some > info, but it closes the window before I can read any of it, so > does anybody have a tip on how I can “freeze” that window > to see what’s getting spit back? Launch a command window, rather than trying to start your app, from IR manager. I -\> Rails Applications -\> Launch Ruby Console Window. If this window opens and stays open, try to start mongrel with c:{RAILS\_ROOT}\mongrel\_rails start If the window closes shortly thereafter, you’ve got a port conflict you need to investigate. Run netstat -a to find out what posts are being used by other apps and either shut down the one that’s running on mongrel’s default port (3000 or 3001) or start mongrel on another port (see mongrl\_rails --help). Holler if you need more help. hth, Bill ---
**Author:** ![lunaclaire](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/f4b2a3/32.png) [@lunaclaire](https://www.ruby-forum.com/u/lunaclaire)\ **Post date:** [July 13, 2007, 1:15am UTC](https://www.ruby-forum.com/t/how-to-debug-failure-on-start-from-instantrails/109164/3 "2007-07-13T01:15:43Z")
Thanks Bill - Didnt know that I could do things that way to start mongrel and keep the window open to see the err msgs. That helped me see a typo created by my editor (UltraEdit) when it tried to be smart and “correct” what it thought was a keyword by putting a leading upper case on a config.action\_controller.xxx property in development.rb all cleaned up now, thanks to you ---
**Author:** ![lunaclaire](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/f4b2a3/32.png) [@lunaclaire](https://www.ruby-forum.com/u/lunaclaire)\ **Post date:** [July 13, 2007, 1:59am UTC](https://www.ruby-forum.com/t/how-to-debug-failure-on-start-from-instantrails/109164/4 "2007-07-13T01:59:45Z")
Happy that helped. Best regards, Bill ----- Original Message ----- From: “lunaclaire” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) To: “Ruby on Rails: Talk” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) Sent: Thursday, July 12, 2007 6:15 PM Subject: [Rails] Re: how to debug failure on start from InstantRails