Hello emmanuel944,
In our case, the files to adjust are located in the following folder on our server that runs the SEP manager software:
'C:\Program Files\Symantec\Symantec Protection Center\data\outbox\agent'
Within the 'agent' folder there are folders with apparently random hexadecimal names such as 'E6B27A700C00000402BF6482CA2B67C0'. We have one of these folders per computer group we have within the SEPM plus one extra for the encompassing "My Company" container.
Within each of these folders, there is a file called 'Profile.xml'. We opened each of these Profile.xml files in WordPad. On the 4th line, it contains 'Name=' and then the name of the computer group for which this file appears to contain the settings.
Doing a search within the file for 'rescan' provides 3 results, all on the same line of the file. The last entry on the line is 'RescanOnDefReload="1"/>'. We changed this '1' to a '0'. As we are unsure how drastic a security risk this might pose for the Cached Files, we also changed value for the 'FileCacheEntries=' to '0' (this is a few items earlier on the same line).
After making these changes, we saved the Profile.xml files. Eventually the server pushed these out to the clients and everything seems to run much smoother ever since.
Keep in mind that making changes in the SEPM program overwrites the Profile.xml files, so we have to double check them after making adjustments in the manager software.
This is how it worked for us, unfortunately I cannot say whether this will work for others. Good luck!