When you'll see this error
You're running a backup job on Windows Server 2016 or 2019 with a tape library like an LTO-8 autoloader. The backup software (maybe Veeam, Backup Exec, or Windows Backup) reports ERROR_MAGAZINE_NOT_PRESENT. The job fails immediately. The exact error code is 0x0000048B.
This usually happens right after a tape change cycle. The changer tried to move a tape from a slot to the drive, but the slot's magazine wasn't physically present. It's not a drive failure — it's a communication issue between the OS and the library's changer mechanism.
Root cause
The SCSI changer driver (mcd.sys on older systems, but the generic changer driver on modern Server) maps logical element addresses to physical slots. When a magazine is removed, those addresses go stale. If backup software queries the changer state before the driver updates, it gets back 0x0000048B.
Three things cause this most often:
- Someone actually pulled a magazine while the system was running
- The library's internal firmware lost track of which slots are populated after a power cycle
- The Windows changer driver didn't refresh its slot inventory after a medium changer reset
Don't bother replacing the tape drive — that's not the issue. The magazine is a separate physical carrier.
Fix it in 4 steps
Step 1: Physically verify magazines
Go look at the library. Open the front door. Count the magazines. Each should be firmly seated. If one's loose or missing, reseat it and close the door. If you've got multiple magazines, note which slots the OS thinks are there versus what's actually loaded.
Step 2: Force a library inventory scan
Run this command from an elevated command prompt on the backup server:
chkntfs /xNo, that's for chkdsk. Use this instead:
mchanger /resetIf mchanger isn't recognized, install the Windows Automated Installation Kit (AIK) — it includes the changer utilities. Or use the library's web interface to trigger a "scan media" action.
Alternatively, open Device Manager, find your tape library under "Medium Changers", right-click and select "Scan for hardware changes". This forces the driver to re-enumerate the changer's slots.
Step 3: Restart the changer service
Stop and restart the Windows Media Changer Service (if running):
net stop mchanger
net start mchangerOn Server 2019 and later, this service might not be installed by default. Instead, reboot the server. Yes, a full reboot. It's faster than digging through event logs for the correct service name.
Step 4: Re-register the changer driver
If steps 1-3 fail, the driver's element map is corrupted. Open Device Manager, expand "Medium Changers", right-click your changer device and choose "Uninstall device". Do NOT check "Delete the driver software for this device". Reboot. Windows will reinstall the driver on startup and re-enumerate elements from scratch.
After the reboot, run a test backup to the same tape set. The error should be gone.
If it still fails after all that
Check the library's firmware version. I've seen 0x0000048B on older Quantum i500 and HP MSL libraries with firmware from 2015 or earlier. Update to the latest firmware from the vendor's support site. This usually fixes stale element mapping after power events.
Also check your backup software's media management settings. Some apps (like Backup Exec) cache the changer state. Clear the cache in the software's tape library settings. The option is usually under "Storage" or "Media" — look for "Rescan" or "Refresh inventory".
Finally, if you're using a SAS or FC connection, swap the cable. Bad cables cause intermittent SCSI sense codes that manifest as ghost errors. It's a long shot, but I've had it happen twice in 14 years.
One last thing: if you're running this on a VM with a pass-through tape library, make sure the hypervisor isn't sharing the changer port with another VM. That'll cause the same error on both VMs.