Why the exclusion list is applicable only for on demand scan,and not for the real protection too…?It seems to me it’s a minus for avast…because if i want to run an application wich avast is considering as a threat(but is a FP for me),my only option is to ignore,and in this case,the “malware” will not be activated and the application wouldn’t run…so,i have to disable the avast’s real time protection(standard shield)… 
It seems to me that an unsual behavior for an antivirus…in fact,all the av that i have tried(no names),have the exclusion option for the real time protection…
It is, but there are two exclusion lists.
For the Standard Shield provider (on-access scanning):
Left click the ‘a’ blue icon, click on the provider icon at left and then Customize.
Go to Advanced tab and click on Add button…
For the other providers (on-demand scanning such as the screen-saver or the Simple User Interface):
Right click the ‘a’ blue icon, click Program Settings.
Go to Exclusions tab and click on Add button…
You can use wildcards like * and ?.
But be careful, you should ‘exclude’ that many files that let your system in danger.
By the way, can you inform the file as being a false positive? (click on the bottom right of the virus warning message).
To know if a file is a false positive, please submit it to VirusTotal and let us know the result. VirusTotal has a file size limit of 10Mb. You can use VirScan also.
If it is indeed a false positive, send it in a password protected zip to virus@avast.com. Please, mention in the body of the message why you think it is a false positive and the password used. Thanks.
Maybe you need to disable Hide protected operating system files and enable View hidden files and folders to manage the file(s).