Hello pgAdmin Support,
I would like to report what appears to be a Windows regression in
pgAdmin 4 version 9.18.
I reproduced the same issue on two different Windows PCs:
- pgAdmin 4 9.17 worked normally.
- After upgrading to pgAdmin 4 9.18, PostgreSQL connections began failing.
Environment
- OS: Windows 11 64-bit
- pgAdmin 4: 9.18
- Previous working version: 9.17
- Bundled psql: PostgreSQL 18.6
- Bundled Python: Python 3.13.14
- PostgreSQL server: PostgreSQL 18 on Ubuntu 24.04
Symptoms
1. When connecting to a PostgreSQL server from pgAdmin 4 9.18, pgAdmin reports:
exception: access violation writing 0x0000000000000000
The pgAdmin log shows the failure in the psycopg/libpq connection path:
psycopg -> pq_ctypes.py -> PQconnectPoll()
ending with:
OSError: exception: access violation writing 0x0000000000000000
I have attached the pgadmin4.log file.
2. The bundled psql.exe also fails when launched normally.
Command:
"C:\Users\<user>\AppData\Local\Programs\pgAdmin 4\runtime\psql.exe" --version
It produces no output and exits with:
-1073741515
Windows also reports that gssapi64.dll cannot be found.
3. However, the required GSSAPI/Kerberos DLL files are actually
present in the pgAdmin installation under:
C:\Users\<user>\AppData\Local\Programs\pgAdmin 4\python
Files confirmed present:
- comerr64.dll
- gssapi64.dll
- k5sprt64.dll
- krb5_64.dll
Other runtime libraries such as libpq.dll, libssl-3-x64.dll,
libcrypto-3-x64.dll, liblz4.dll, libzstd.dll, libiconv-2.dll, and
libintl-8.dll are also present in the pgAdmin installation.
Workaround / reproduction detail
If I manually add both the pgAdmin Python and runtime directories to
PATH in PowerShell:
$rt = "C:\Users\<user>\AppData\Local\Programs\pgAdmin 4\runtime"
$py = "C:\Users\<user>\AppData\Local\Programs\pgAdmin 4\python"
$env:Path = "$py;$rt;$env:Path"
then:
& "$rt\psql.exe" --version
works correctly and returns:
psql (PostgreSQL) 18.6
Using the same environment, the bundled psql.exe can also successfully
connect to the remote PostgreSQL server.
This indicates that the PostgreSQL server configuration, pg_hba.conf,
authentication, network connectivity, and credentials are working
correctly.
Because the same behavior occurred on a second PC immediately after
upgrading from 9.17 to 9.18, this looks like a pgAdmin 4 9.18 Windows
packaging/runtime DLL search-path regression, particularly around the
bundled GSSAPI/Kerberos libraries.
Could you please check whether pgAdmin 4 9.18 on Windows is missing
the required DLL search-path initialization for the bundled
Python/runtime directories?
Please let me know if you need any additional logs or diagnostics.
Best regards
2026-09-18 17:32:07,205: WARNING werkzeug: Werkzeug appears to be
used in a production deployment. Consider switching to a production web server
instead.
2026-09-18 17:32:45,269: ERROR pgadmin: exception: access violation
writing 0x0000000000000000
Traceback (most recent call last):
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\web\pgadmin\browser\server_groups\servers\__init__.py", line 1376, in create
status, errmsg = conn.connect(
~~~~~~~~~~~~^
password=password,
^^^^^^^^^^^^^^^^^^
...<2 lines>...
server_types=ServerType.types()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\web\pgadmin\utils\driver\psycopg3\connection.py", line 380, in connect
pg_conn = psycopg.Connection.connect(
connection_string,
cursor_factory=DictCursor,
prepare_threshold=manager.prepare_threshold)
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\python\Lib\site-packages\psycopg\connection.py", line 109, in connect
rv = waiting.wait_conn(gen, interval=_WAIT_INTERVAL)
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\python\Lib\site-packages\psycopg\waiting.py", line 118, in wait_conn
fileno, s = gen.send(ready)
~~~~~~~~^^^^^^^
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\python\Lib\site-packages\psycopg\_connection_base.py", line 441, in
_connect_gen
pgconn = yield from generators.connect(conninfo, timeout=timeout)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\python\Lib\site-packages\psycopg\generators.py", line 84, in _connect
status = conn.connect_poll()
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\python\Lib\site-packages\psycopg\pq\pq_ctypes.py", line 127, in connect_poll
return self._call_int(impl.PQconnectPoll)
~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\python\Lib\site-packages\psycopg\pq\pq_ctypes.py", line 814, in _call_int
return func(self._pgconn_ptr)
OSError: exception: access violation writing 0x0000000000000000
2026-09-18 17:35:50,912: ERROR pgadmin: exception: access violation
writing 0x0000000000000000
Traceback (most recent call last):
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\web\pgadmin\browser\server_groups\servers\__init__.py", line 1376, in create
status, errmsg = conn.connect(
~~~~~~~~~~~~^
password=password,
^^^^^^^^^^^^^^^^^^
...<2 lines>...
server_types=ServerType.types()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\web\pgadmin\utils\driver\psycopg3\connection.py", line 380, in connect
pg_conn = psycopg.Connection.connect(
connection_string,
cursor_factory=DictCursor,
prepare_threshold=manager.prepare_threshold)
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\python\Lib\site-packages\psycopg\connection.py", line 109, in connect
rv = waiting.wait_conn(gen, interval=_WAIT_INTERVAL)
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\python\Lib\site-packages\psycopg\waiting.py", line 118, in wait_conn
fileno, s = gen.send(ready)
~~~~~~~~^^^^^^^
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\python\Lib\site-packages\psycopg\_connection_base.py", line 441, in
_connect_gen
pgconn = yield from generators.connect(conninfo, timeout=timeout)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\python\Lib\site-packages\psycopg\generators.py", line 84, in _connect
status = conn.connect_poll()
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\python\Lib\site-packages\psycopg\pq\pq_ctypes.py", line 127, in connect_poll
return self._call_int(impl.PQconnectPoll)
~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
File "C:\Users\withk\AppData\Local\Programs\pgAdmin
4\python\Lib\site-packages\psycopg\pq\pq_ctypes.py", line 814, in _call_int
return func(self._pgconn_ptr)
OSError: exception: access violation writing 0x0000000000000000
