Namespace route can't be blank

Summary

When editing a user and clicking "Save changes", the following error gets displayed:

The form contains the following error:

    Namespace route can't be blank

Steps to reproduce

This instance of GitLab was migrated from a source-based 9.2.10-ee installation to a 9.2.10-ee omnibus package (different host), also also from a standalone MySQL database to the omnibus-embedded PostgreSQL database (by following the documentation provided in the GitLab EE repo) and then upgraded with the omnibus package for 9.4.5 via Apt.

Besides that:

Go to a user other than yourself (admin), click on "Save changes"

Example Project

n/a

What is the current bug behavior?

Displaying the error mentioned above.

What is the expected correct behavior?

Not displaying the error mentioned above.

Relevant logs and/or screenshots

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info

System information
System:		Debian 9.1
Proxy:		no
Current User:	git
Using RVM:	no
Ruby Version:	2.3.3p222
Gem Version:	2.6.6
Bundler Version:1.13.7
Rake Version:	10.5.0
Redis Version:	3.2.5
Git Version:	2.13.4
Sidekiq Version:5.0.0
Go Version:	unknown
GitLab information
Version:	9.4.5-ee
Revision:	00ce12f
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	postgresql
DB Version:	9.6.3
URL:		https://gitlab.mfb.io
HTTP Clone URL:	https://gitlab.mfb.io/some-group/some-project.git
SSH Clone URL:	git@gitlab.mfb.io:some-group/some-project.git
Elasticsearch:	yes
Geo:		no
Using LDAP:	no
Using Omniauth:	yes
Omniauth Providers: azure_oauth2
GitLab Shell
Version:	5.3.1
Repository storage paths:

• default: /var/opt/gitlab/git-data/repositories Hooks: /opt/gitlab/embedded/service/gitlab-shell/hooks Git: /opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check

Checking GitLab Shell ...
GitLab Shell version >= 5.3.1 ? ... OK (5.3.1)
Repo base directory exists?
default... yes
Repo storage directories are symlinks?
default... no
Repo paths owned by git:root, or git:git?
default... yes
Repo paths access is drwxrws---?
default... yes
hooks directories in repos are links: ...
3/2 ... yes
[more repositories]
90/1165 ... yes
debian-packages / librdkafka ... ok
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Check GitLab API access: OK
Access to /var/opt/gitlab/.ssh/authorized_keys: OK
Send ping to redis server: OK
gitlab-shell self-check successful
Checking GitLab Shell ... Finished
Checking Sidekiq ...
Running? ... yes
Number of Sidekiq processes ... 1
Checking Sidekiq ... Finished
Checking Reply by email ...
Reply by email is disabled in config/gitlab.yml
Checking Reply by email ... Finished
Checking LDAP ...
LDAP is disabled in config/gitlab.yml
Checking LDAP ... Finished
Checking GitLab ...
Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... yes
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...
3/2 ... yes
[more repositories]
90/1165 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.3.3 ? ... yes (2.3.3)
Git version >= 2.7.3 ? ... yes (2.13.4)
Active users: ... 167
Elasticsearch version 5.1 - 5.3? ... yes (5.3.3)
Checking GitLab ... Finished

Possible fixes