Written 5 Sep 2026. This is a how-to, not a product card.
When you can open the house share but can't write
The house folder opens, but copy, save, or phone upload fails. Check disk room, Samba read only, then folder ownership. You don't need a NAS.
Can't open the folder at all? That wider walk is when the house share won't open. Haven't made a share yet? Start with a file share. This note is for the annoying middle case: you already see the folder, login worked, and a write still fails.
Skip until the folder opens
If Finder, File Explorer, or the phone never shows the share, stop here. Fix open first: when the house share won't open. Don't buy a NAS because one copy into a folder failed. Don't open SMB to the internet to "test" a write.
What this is
Open and write are different jobs. Samba can let you see the folder and still refuse a save. Common causes: the disk is full, the share is marked read-only in smb.conf, the Linux folder is owned by the wrong user, or the phone/laptop is still using an old guest or read-only bookmark. The order below is cheap checks first.
Step 1: awake, then SSH
Power light. Fan. If it looks asleep, start with is the computer still on?. You need SSH from the couch: SSH from the couch. Connect fails? when SSH won't connect.
Step 2: copy the exact write error
On the laptop or phone, try one small text file. Save the exact words:
| What you see | Likely cause |
|---|---|
| Disk full / no space left / not enough free space | System disk or share disk is packed. Go to step 3. |
| Access denied / you don't have permission / read-only volume | Samba read only, wrong Linux owner, or a guest/read-only login. Steps 4–6. |
| Folder opens, paste or upload spins then fails with no clear line | Still treat as write. Check disk, then ownership. Phones often hide the real error. |
| Login / password failed before the folder opens | Wrong page. That is open/login: when the house share won't open. |
Step 3: rule out a full disk
Print human sizes:
df -h /
Point at the line that ends in /. If Use% is 95–100% (or Avail is tiny), free room first: when the computer's disk is full. Quieter look before anything fails: see if the computer still has room.
If the house folder already lives on a USB that stays plugged in, check that mount too:
df -h /srv/share
Swap the path if yours differs. A full stay-in USB looks like "can't write" on phones. Bigger stick walk: put the house folder on a USB disk. A backup stick you unplug for weekly copies is a different page: when the backup USB is full.
Step 4: confirm Samba allows writes
Show the live share block (swap photos if you used another share name):
testparm -s | sed -n '/^\[photos\]/,/^\[/p'
Or open the file:
sudo nano /etc/samba/smb.conf
Inside that share block you want:
read only = no
If you see read only = yes, or writable = no, change it to allow writes, save, then:
testparm -s
sudo systemctl restart smbd
Try the small file again from the laptop before you chase Linux permissions.
Step 5: fix folder ownership
Samba writes as the Samba user you logged in with. That Linux user has to own the folder (or be in a group that can write). See who owns it:
ls -ld /srv/share
Swap the path if yours differs. Then hand it to your login (the same name you use for Samba):
sudo chown youruser:youruser /srv/share
Optional, if new files still land wrong for a second person later:
sudo chmod u+rwx /srv/share
Don't chmod the whole computer. Don't chmod -R 777 /. A second person on the same folder is add another person to the house share. A second folder is add a second house share.
Step 6: stale login or a read-only bookmark
Windows, Mac, and phones love remembering an old guest or wrong password. After you change Samba settings, clear the saved copy and open again: forget the saved house-share login. Reset the Samba password itself: set or change the house-share password.
On a phone, delete the bookmark and reconnect with the share user (not guest). Open walks: open the house share from a phone, from a laptop.
Step 7: confirm with one small write
From the laptop or phone on house Wi-Fi, copy a tiny text file in. Then from SSH:
ls -la /srv/share
You should see the new file owned by your user. Phone photo dump next: save phone photos to the house share. If the folder never opens, flip back to when the house share won't open. If Samba itself vanished, when the house share disappeared, check the computer.
What this is not
This is not a reason to buy a NAS tonight. It is not RAID. It is not opening SMB past the house network. It is not the "folder won't open" page (that is when the house share won't open). It is not deleting the only backup to free the live disk.
What next
Keep a second copy of the house folder: a backup of the house folder. Watch disk room: see if the computer still has room. Second folder: add a second house share. Second login on the same folder: add another person to the house share. Map a drive letter: map the house share as a drive.
Optional: note which write error you hit in Lab plan — username + passkey, no email. Skip if you just want to keep reading.
Skip
- Skip buying a NAS because one copy failed.
- Skip opening SMB to the internet.
- Skip
chmod -R 777 /. - Skip deleting the only backup to free the live disk.
- Skip this page if the folder never opens — use when the house share won't open.
Sources
Samba: smb.conf (read only). Samba wiki: standalone server. Ubuntu Server: Samba file server. Official pages only. For the share itself, see a file share. For open failures, see when the house share won't open. For a full disk, see when the computer's disk is full.