2

Well firstly avast doesn’t block/prevent from runing, it scan and alerts you if a file is infected.
Are you saying avast detects weatherbug as infected ?
If so what is the virus name, file name and location of the infected file ?

If so 2. You could also check the offending/suspect file at: VirusTotal - Multi engine on-line virus scanner
Or Jotti - Multi engine on-line virus scanner if any other scanners here detect them it is less likely to be a false positive. You can’t do this with the file in the chest, you will need to move it out.

If it is indeed a false positive, add it to the exclusions lists (Standard Shield, Customize, Advanced and Program Settings, Exclusions) and periodically check it (scan it in the chest), there should still be a copy in the chest even though you restored it to the original location. When it is no longer detected then you can also remove it from the Standard Shield and Program Settings, exclusions.
Also see (Mini Sticky) False Positives, how to report it so the problem can be corrected.