Q4OS Forum

drpeppercan

Member

Registered: 2025-09-27

Posts: 2

"sddm-greeter not writable" error

Hi all.
I am about to try to fix this. I just need someone to confirm that my next steps are what I need.

Background: I shrank the main partition to create another partition for backups (1st level). Then I created a dir for the backups in mnt. Then I mounted it. It checked good so I unmounted it. Then I added its UUID to the fstab file and took ownership of the new partition with chown and rebooted.
However, just before Q4OS loaded it showed me a pop up window saying:
[Configuration file "/var/lib/ssdm/.config/sddm-greeter" not writable.]

Next steps:

1. sudo chown -R sddm:sddm /var/lib/sddm/.config
2. sudo systemctl restart sddm

That's it.
What do you think?
-------------------------------------------------
-- UPDATE --
I did not have the chance to do the steps above, unfortunately.
This pc was turned off, and now it cannot load Q4OS.
A couple of things failed to load:
"Failed to start cups.service - CUPS Scheduler."
"Failed to start nmbd.service - Samba NMB Daemon."

[I think I'm still not allowed to post images]
imgur.com/H9Nb9TO

I asked Monica AI and she said this [what do you guys think?]:

**Resolving the SDDM Greeter Configuration Error in Q4OS**

The error `Configuration file "/var/lib/ssdm/.config/sddm-greeter" not writable` indicates a permissions issue with the SDDM display manager’s configuration file. Here’s how to diagnose and fix it:

---

### 1. **Root Cause Analysis** 
   - **SDDM permissions**: The SDDM service (which manages the login screen) runs under the `sddm` user. The error occurs because: 
     - The directory `/var/lib/ssdm/.config` or the file `sddm-greeter` lacks write permissions for the `sddm` user. 
     - Ownership of these files/directories was accidentally altered during your `chown` operation on the backup partition. 

---

### 2. **Immediate Fix** 
   - **Step 1: Boot into recovery mode** 
     Reboot Q4OS, hold `Shift` to access GRUB, and select **Recovery Mode** → **Root shell**. 
   - **Step 2: Repair permissions**: 
     ```bash 
     chown -R sddm:sddm /var/lib/ssdm 
     chmod 755 /var/lib/ssdm/.config 
     chmod 644 /var/lib/ssdm/.config/sddm-greeter 
     ``` 
   - **Step 3: Reboot**: 
     ```bash 
     reboot 
     ``` 

---

### 3. **Verify Backup Partition Configuration** 
   - **Check fstab entry**: 
     Ensure your backup partition’s UUID and mount point in `/etc/fstab` are correct. Example: 
     ```bash 
     UUID=1234-ABCD /mnt/backup ext4 defaults 0 2 
     ``` 
   - **Test mount**: 
     ```bash 
     sudo mount -a 
     ``` 
     If errors occur, review the UUID with `blkid` and correct typos. 

---

### 4. **Prevent Future Issues** 
   - **Avoid broad `chown` commands**: 
     When changing ownership, target specific directories (e.g., `/mnt/backup`), not entire system paths like `/mnt`. 
   - **Backup critical files**: 
     Before editing system files (e.g., `fstab`), create backups: 
     ```bash 
     sudo cp /etc/fstab /etc/fstab.bak 
     ``` 

---

### 5. **Post-Fix Validation** 
   - Confirm SDDM starts correctly: 
     ```bash 
     systemctl status sddm 
     ``` 
   - Test backup partition functionality: 
     ```bash 
     ls -l /mnt/backup  # Verify ownership and accessibility 
     ``` 

---

**Why This Happened** 
Your `chown` command likely altered permissions for `/mnt` or its subdirectories, indirectly affecting system services like SDDM that rely on specific user/group ownership. Always double-check paths when modifying permissions.

bin

Member

From: U.K.

Registered: 2016-01-28

Posts: 1,562

Re: "sddm-greeter not writable" error

On my Plasma 5.8 system sddm-greeter appears in:
/usr/bin
/var/lib/sddm/.cache
/etc/pam.d

Possibly it may have changed place in 6.1

Have you actually verified the location of the file whose permissions you are trying to alter? NOTE ssdm does not exist, it is sddm

The key to this is to know exactly what command sequence you used when taking ownership of the new partition.
If you boot the machine with live media you can access the .bash-history file and get that information.
I would also suggest you copy the fstab tab contents.
Finally whilst in live mode please run inxi -Fxxxmprz and copy the output back here.

drpeppercan

Member

Registered: 2025-09-27

Posts: 2

Re: "sddm-greeter not writable" error

Thank you so much for your support bin.
I'll get back to you asap.