I already did that thrice. What I've done now is deleted the last few block files from bitcoin core corresponding to about where that recurring 99%-ish point would be(going by the logs), and restarted it with -reindex. Once it's back up to sync I will -AGAIN- rebuild the armory DB.
Your issue reminds me on mine serveral months ago. Are you using any Anti-Virus software, NAS or encrypted HDD?
No encrypted HDD, no NAS, and antivirus already excludes the Armory folder(which cotains both ADB and Bitcoin blockchain) due to some well-known trolling events where ppl deliberately included transaction bytes to resemble malware and flag false-positives.