Plesk is not accessible due to "Permission denied" error: Lock Manager error: Can't open or create shared memory by shm.name

Gilson Siqueira

Updated February 02, 2026 15:38

Plesk for Windows Plesk for Linux kb: technical

Applicable to:

Unable to log in to Plesk:

PLESK_ERROR: Internal error:
Lock Manager error: '[LockManagerException] Can't open or create shared memory by shm.name: "/run/lock/lmlib/SharedLockManagerStorage0.2.3"; shm.start_size: "8388608"; error "Permission denied"'.
Message Lock Manager error: '[LockManagerException] Can't open or create shared memory by shm.name: "/run/lock/lmlib/SharedLockManagerStorage0.2.3"; shm.start_size: "8388608"; error "Permission denied"'.
File Hierarchical.php
Line 126
Type Plesk\Lock\Exception
The same error messages appear in /var/log/plesk/panel.log:

CONFIG_TEXT: ERR [panel] [LockManagerException] Can't open or create shared memory by shm.name: "/run/lock/lmlib/SharedLockManagerStorage0.2.3"; shm.start_size: "8388608"; error "Permission denied"
ERR [panel] Lock Manager error: '[LockManagerException] Can't open or create shared memory by shm.name: "/run/lock/lmlib/SharedLockManagerStorage0.2.3"; shm.start_size: "8388608"; error "Permission denied"'.:
The following error appears while working in Plesk:

PLESK_ERROR: Type Plesk\Lock\Exception
Message Lock Manager error: '[LockManagerException] Can't open or create shared memory by shm.name: "Global\TmpSharedLockManagerStorage_v2"; shm.start_size: "131072"; error "The system cannot find the file specified."'.
File Hierarchical.php
Line 126

The Plesk Lock Manager shared memory segment is corrupted, missing, or has incorrect permissions.

Plesk for Linux

Connect to the server via SSH.
Run the Plesk installer to reinstall updates and refresh system files:
```
# plesk installer update
```

Plesk for Windows

Connect to the server via RDP.
Start a Command Prompt as an Administrator.
Reinstall Plesk updates:
```
C:\> plesk installer update
```
Repair the Plesk installation permissions. Navigate to the bin directory:
```
C:\> cd %plesk_dir%admin\bin
```
Run the reconfigurator.exe utility.
Click the Repair Plesk Installation button.
Select the following checkboxes:
- Plesk Server Accounts
- Plesk File Security
- Plesk Services
Click the Check button to apply the fixes.