Startup is really slow for all Cygwin applications

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Eventually I found what causes this issue, but I’m still not sure why. Cygwin works for other people in same environment very well.

Cause: On the start of every Cygwin application it tries to get credentials as it is described in etc/nsswitch.conf file. For some reason, it takes a lots of time for my account as it contacts with several Active Directory domain controllers via LDAP.

Solution 1: You can save the current user and group in etc/passwd and etc/group files and set Cygwin to check them before Active Directory.

  1. Start mintty.exe and wait till it opens
  2. Run mkpasswd -c and save its output to etc/passwd file (you will have to create it, output should be one line)
  3. Run mkgroup -c and save its output to etc/group file (you will have to create it, output should be one line)
  4. Open etc/nsswitch.conf and write

nsswitch.conf contents:

passwd: files # db
group:  files # db

Now your Cygwin should start immediately.

Solution 2: There is special CygServer application, shipped with Cygwin, which can be started as an NT service or as a simple process (just run usr/sbin/cygserver.exe). It caches credentials and propagates them to every next Cygwin process while cygserver is running.

Add it to startup or start it before your Cygwin session and you’re good — cygserver startup will take time, but every next Cygwin process will start immediately.

Is it your case? I want to share my investigation steps, so you could check, if your case is same to mine.

  • Install MS Network Monitor as it is able to show traffic from a specific process. Run it as administrator.
  • Create New capture tab and click Start (you don’t have to add any filters or anything).
  • Start mintty and you will see its connections in netmon: netmon-screenshot
  • You will see list of mintty connections in the tree view on the left and TCP and LDAP frames on the right after selecting on of those connections.
  • Additionally, you can get name of those remote machines by IP address. Run nbtstat -a 8.8.8.8 in command line (replace 8.8.8.8 by one of IP addresses from netmon).

Going deeper: I’m still playing with etc/nsswitch.conf file to get local credentials or maybe cached ones so it will run faster without cygserver. But no luck yet.

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