I am using the Simple recovery model and I'm taking a weekly full backup each Monday morning with differentials taken every 4 hours during the day.

On Wednesday afternoon, a programmer ran a process that corrupted the db and I had to restore to the most recent differential. It was 5pm in the afternoon and a differential backup had just occured at 4pm. No problem, I figured.

I restored the full backup from Monday morning and tried to restore the most recent differential backup. The differential restore failed. Since I had used T-SQL for the initial attempt, I tried using Enterprise Manager to try again.

When viewing the backup history, I see my initial full backup taken on Monday plus all the differentials. BUT, on closer inspection, I noticed another full backup in the backup history that was taken early Tuesday morning. I can't figure out where this Tuesday morning full backup came from. It wasn't taken by me (or scheduled by me) and I'm the only one with access to the server. My full backups are usually named something like HCMPRP_20070718_FULL.bak. This erroneous full backup was named something like HCMPRP_03a_361adk2k_dd53.bak. It seemed like it was a system generated name. Not something I would choose. To top it off, I could not find this backup file anywhere on the server and when I tried to restore using this full backup, it failed.

Does anyone have any clues as to where this full backup might come from Does SQL Server trigger a full backup on its own if some threshold is reached

I ended up having to restore using the differential taken just before this erroneous full backup and lost a day of transactions.

Any insight is greatly appreciated.

Re: Differential backup fails because of erroneous full backup

Deepak Rangarajan

No SQL server will not trigger a backup of its own........just check in the error log when the last full backup was made.....and see if the errorenous full backup name was present in the errorlog..........

Re: Differential backup fails because of erroneous full backup


Thanks for the response. It turns out that there was someone else who had access to the server (unbeknownst to me) that triggered the full back up. Unfortunately, this individual did not know what he was doing and deleted the full backup file shortly after it completed. This, of course, screwed up my differentials.