“update” will damage your computer. You should move it to the Trash.
When I click move to the trash nothing ends up in the trash and I keep getting this error. So far I've found nothing to solve this.
Look in your Downloads folder.
It could be anywhere, though.
You might try running Etrecheck or MalwareBytes Anti-Malware for Mac. One of those may identify it.
Note that it may not appear in those programs as "update." It may be part of some Adware package.