Everytime Bootup Window says can't find rdtmpmst.dll

[hapzunglam]

Everytime when the system starts up windows have a pop up says can't find C:\Users\XXXXX\AppData\Local\Temp\rdtmpmst.dll 

When I look for this file in registry.  It goes under Avast PUB_remove .  If I try to remove that line in the registry it wouldn't let me it says it cannot be remove.

What should I do?

[bob3160]

Repair & Clean Install of Avast https://goo.gl/t7aJGq
Repair Avast:
Open the Avast User Interface > Menu > Settings > Troubleshooting > Repair App. > Restart the Computer or,
Control Panel> Program and Features (Add/remove program)>Select Avast> Select Repair. Reboot when completed
https://www.avast.com/faq.php?article=AVKB204

If Repair doesn't fix the problem, try the following:
If your Avast settings are not the default settings and you want them restored after the Clean Install, follow this before removing Avast.
https://goo.gl/TXjM7h
Clean Install of Avast:
https://goo.gl/4Ptzkf
If you need additional help with the Clean Install, watch this:
https://youtu.be/p-h3myRD51A

[kwiq]

Hi hapzunglam,
avast registry keys are protected by self defense component you can try to disable it in advance settings and remove/rename rdtmpmst.dll . If it will not help you can boot into safe mode and remove it as avast is not active in safe mode.

I wonder which process creates the popup dialog,  procmon is able to capture boot activity and find a process which tried to open rdtmpmst.dll

1) download procmon from (https://docs.microsoft.com/en-us/sysinternals/downloads/procmon)
2) Run is as admin and in Menu -> Options -> check Enable Boot Logging
3) Restart PC
4) Run procmon as admin again this time it will ask you where you want to save boot log
5) zip the log as hapzunglam_6_2019.zip and upload it to avast ftp server ftp://ftp.avast.com/incoming (https://support.avast.com/en-eu/article/FTP-file-upload)

Thank you for report !