How to install a old virus definition file and search modul?

i give up.

why do you want to install a old virus definition file?
anyway, as far as i know it is not possible, only lates is available for download and is updated evry day https://www.avast.com/download-update
and avast will autoupdate to latest when connected so dont understand what it is you are trying to do here!!

what do you mean by search module?

not only the virus definition wil be updated, there is a search-module which also be updated sometimes when you use a old program version its always possible to use new virus definition, because the search engine will be also updated.
https://forum.avast.com/?topic=169233.0

Provided you have a relatively recent version of avast (see https://www.avast.com/download-update) then it would be using the same type/version of the VPS.

So avast 9 or avast 10 would be using the same virus definitions update from within the avastUI.

Referring to the link that you have provided. Is your support ticket being replied from time to time? Make sure you follow the support technician exact instruction? On that link read Asyn first comment he said “Other security related software installed”. If you can’t remember or forgot what antivirus software your computer got installed I am sure these issue(s) will be coming up and I think these issue(s) are related to that. What antivirus software did your computer come pre-installed with? In your 5th comment you even mentioned that you are using an very outdated version of Avast version 6.0.1506.

Did you do a complete scan of malware by Malwarebytes antimalware and superantispyware and avast? Also did you do a scan with AdwCleaner? If no malware found, my best suggestion is to back up all of your personal files and do a factory recovery of your computer. After that make sure you have the latest Service Pack (SP3) and install all important updates. Once that has been done, uninstall your current antivirus software via add/remove and follow the instructions. After that has been done, download it’s uninstall utility https://singularlabs.com/uninstallers/security-software/ and run it in safe mode. Once that has been done. Reinstall avast and after installation has been done it will do a quick start up scan. Once done, restart your computer manually and after restart register your copy of avast.

That’s up to you or you can find another antivirus. If you get another antivirus, uninstall avast via add/remove, download it’s uninstall utility and run it. The tool will let you know that this tool will run your computer automatically in safe mode, click ok on both, and follow the instructions. After that install your new antivirus, depending upon the antivirus installed it will let you know to restart your computer in order for the installation to be successfully. If it doesn’t say, restart your computer manually.

good idea, but the last 5 years was only avast installed and i used te avastclear removal tool alot of times without any effect. last week was it good, but today was the error again. i dont believe that it have to do with my computer.

dont believe that it have to do with my computer.
To find out, post Farbar Recovery Scan Tool logs