Question: The title says it all. Just to add that the number can be multiple digits.

I'm using the following function:

```
str_replace( "/^\&DaysAgo=d+$/", "", $save_query);

```

Answer: 
After a lot of research in Sitecore.Kernel.dll I found the solution.
After the "INFO Committing files." log entry there was another entry: "Job started: WatchStatus". This Job never ended.

The `ItemInstaller` is responsible for the "Installing item:" logs and the `BlobInstaller` is responsible for the "Installing of blob values has been finished" log.
In the `InstallPackageForm` class, the function `WatchForInstallationStatus()` is responsible for the "Job started: WatchStatus" logmessage. This function starts a new thread in which it checks the status of the package installation which is stored in the temp folder.
In my case, the IIS\_IUSRS role did not have write rights on the temp folder. After I changed it, it worked.

This is what the log file should look like:

```
ManagedPoolThread #7 12:45:57 INFO  Committing files.
ManagedPoolThread #11 12:45:57 INFO  Job started: WatchStatus
ManagedPoolThread #7 12:45:57 INFO  Job ended: Install (units processed: )
ManagedPoolThread #11 12:45:58 INFO  Job ended: WatchStatus (units processed: )
ManagedPoolThread #8 12:45:58 INFO  Job started: InstallSecurity
ManagedPoolThread #8 12:45:58 INFO  Installing security from package: <package>

```
After the default installation of 8.0 Update 4 you need to run mongo manually. 

The easiest way is to install mongo by default and run it from command prompt as: mongod.exe --dbpath c:\example\_of\_my\_mongo\_database\_dir 

The best way is to install it as a windows service - <http://mikerobbins.co.uk/2015/02/02/install-mongodb-as-a-windows-service-for-sitecore/>

As soon as you do that - you'll be able to install the packages without any problem.