Hi ,
I am trying to migrate version 3 hosted in VM to version 4 by following the migration guide found here Migrating from ERPNext version 3 · frappe/bench Wiki · GitHub
all the steps went smoothly and reached the section -
Install bench
cd /home/erpnext
git clone GitHub - frappe/bench: CLI to manage Multi-tenant deployments for Frappe apps bench-repo
sudo pip install -e bench-repo
Setup ERPNext on the new bench
cd ~
bench init frappe-bench
cd frappe-bench
but after than when i execute his migration command like -
bench migrate-3to4 /path/to/old/erpnext/folder with chaning my old erpnext folder location it is giving following error . Kindly help. 
bench migrate-3to4 /home/erpnext/erpnext/conf.py
Traceback (most recent call last):
File “/home/erpnext/bench-repo/bench/migrate3to4.py”, line 106, in
main(args.site)
File “/home/erpnext/bench-repo/bench/migrate3to4.py”, line 38, in main
site = copy_site(path)
File “/home/erpnext/bench-repo/bench/migrate3to4.py”, line 49, in copy_site
raise Exception(“Site already exists”)
Exception: Site already exists
Error: None
Traceback (most recent call last):
File “/usr/local/bin/bench”, line 9, in
load_entry_point(‘bench==0.1’, ‘console_scripts’, ‘bench’)()
File “/home/erpnext/bench-repo/bench/cli.py”, line 29, in cli
return bench()
File “/usr/local/lib/python2.7/dist-packages/click/core.py”, line 610, in call
return self.main(*args, **kwargs)
File “/usr/local/lib/python2.7/dist-packages/click/core.py”, line 590, in main
rv = self.invoke(ctx)
File “/usr/local/lib/python2.7/dist-packages/click/core.py”, line 936, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File “/usr/local/lib/python2.7/dist-packages/click/core.py”, line 782, in invoke
return ctx.invoke(self.callback, **ctx.params)
File “/usr/local/lib/python2.7/dist-packages/click/core.py”, line 416, in invoke
return callback(*args, **kwargs)
File “/home/erpnext/bench-repo/bench/cli.py”, line 162, in migrate_3to4
site=path))
File “/home/erpnext/bench-repo/bench/utils.py”, line 59, in exec_cmd
subprocess.check_call(cmd, cwd=cwd, shell=True)
File “/usr/lib/python2.7/subprocess.py”, line 511, in check_call
raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command ‘env/bin/python /home/erpnext/bench-repo/bench/migrate3to4.py /home/erpnext/erpnext/conf.py’ returned non-zero exit status 1
