Startup is really slow for all Cygwin applications

Question

Start of any Cygwin application takes more than a minute on Windows 8.1 x64. It doesn't matter, either I'm starting mintty from shortcut or cygwin.bat or ls.exe or bash.exe from bin folder. Each of them will be slow.

After Bash or mintty is started they are working fairly quick:

$ time for i in {1..10} ; do bash -c "echo Hello" ; done
Hello
...
Hello

real    0m1.273s
user    0m0.060s
sys     0m1.181s

Steps, which I've tried:

• Reinstalled and tried both Cygwin and Cygwin64 a few times (version 2.864)
• Started them as Administrator
• Tried to run them in Windows 7 compatibility mode
• Disabled "Automatically detect settings" for LAN as in this reply
• Added 127.0.0.1 localhost cygdrive wpad to hosts as in same reply
• Set antivirus to disabled state
• Checked that Bash completion is not installed (no /etc/bash_completion.d folder)
• Disabled all removable drives in Device Manager (only system SSD and data HDD left)
• Tried to run with empty etc/profile.d folder
• Tried to run with empty etc/bash.bashrc file

How else can I find root cause?

P.S. - I have two different systems, laptop and desktop both with Windows 8.1 64 bit. This issue it 100% reproducible on both.

Also, if I start Bash a few seconds after login it starts immediately.

Answer 1

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:
  

• 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.

Answer 2

Here's what worked for me.

1. Launch Cygwin terminal and then run the following two strings.

   mkpasswd -c > /etc/passwd
   mkgroup -c > /etc/group
   

2. Edit your "/etc/nsswitch.conf" file to contain the following two lines.

   passwd:   files # db
   group:    files # db
   

3. Relaunch Cygwin.

Cygwin opens quickly.

Answer 3

If you are on a network with a large AD directory mkpasswd will take a lot of time (several days in my case). So consider using:

mkpasswd -c -l > /etc/passwd
mkgroup -c -l > /etc/group

 -l,--local [machine]    Print local user accounts of \"machine\",
                         from local machine if no machine specified.
                         Automatically adding machine prefix for local
                         machine depends on settings in /etc/nsswitch.conf.

Answer 4

Adding 'C:\cygwin64\bin' to the path worked for me.