Chiudendo Safari mi si blocca tutto

[Daniel X]

Buonasera, mi è successo ieri e pure oggi, che ogni tanto chiudendo Safari cliccando sulla x rossa il mio MacBook pro Retina 15" metà 2014 aggiornato ad El Capitan non risponda più ai comandi, e vada totalmente in blocco. Soltanto dopo qualche secondo si riprende ma se riapro Safari è lento e chiudendolo succede nuovamente. Per risolvere sono costretto a riavviare il Mac. Tutto questo con Yosemite non succedeva e mi sta facendo salire la rabbia. Vi posto una scansione di EtreCheck qualora potesse esservi utile a capire il problema e vi ringrazio in anticipo. Cosa potrebbe essere?

 

EtreCheck version: 2.5.5 (215)

Report generated 21/10/15, 12:17
Runtime 1:16
Download EtreCheck from http://etresoft.com/etrecheck

Click the [Click for support] links for help with non-Apple products.
Click the [Click for details] links for more information about that line.

Hardware Information: (What does this mean?)
    MacBook Pro (Retina, 15-inch, Mid 2014) 
    [Click for Technical Specifications]
    [Click for User Guide]
    MacBook Pro - model: MacBookPro11,2
    1 2,5 GHz Intel Core i7 CPU: 4-core
    16 GB RAM Not upgradeable
            BANK 0/DIMM0
            8 GB DDR3 1600 MHz ok
        BANK 1/DIMM0
            8 GB DDR3 1600 MHz ok
    Bluetooth: Good - Handoff/Airdrop2 supported
    Wireless:  en0: 802.11 a/b/g/n/ac
    Battery: Health = Normal - Cycle count = 48 - SN = D865155Y78BFWF8BW

Video Information: (What does this mean?)
    Intel Iris Pro
        Color LCD 2880 x 1800

System Software: (What does this mean?)
    OS X El Capitan 10.11 (15A284) - Time since boot: less than an hour

Disk Information: (What does this mean?)
    APPLE SSD SM0256F disk0 : (251 GB) (Solid State - TRIM: Yes)
        EFI (disk0s1) <not mounted> : 210 MB 
        Macintosh HD (disk0s2) / : 250.14 GB (209.73 GB free)
        Recovery HD (disk0s3) <not mounted>  [Recovery]: 650 MB 

USB Information: (What does this mean?)
    Apple Inc. Apple Internal Keyboard / Trackpad 
    Apple Inc. BRCM20702 Hub 
        Apple Inc. Bluetooth USB Host Controller 

Thunderbolt Information: (What does this mean?)
    Apple Inc. thunderbolt_bus

Gatekeeper: (What does this mean?)
    Mac App Store and identified developers

Kernel Extensions: (What does this mean?)
        /System/Library/Extensions
    [not loaded]    com.devguru.driver.SamsungComposite (1.4.32 - SDK 10.6) [Click for support]

User Login Items: (What does this mean?)
    iTunesHelper    Applicazione  (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)

Other Apps: (What does this mean?)
    [running]    com.etresoft.EtreCheck.97632

Internet Plug-ins: (What does this mean?)
    Default Browser: Version: 601 - SDK 10.11
    QuickTime Plugin: Version: 7.7.3

3rd Party Preference Panes: (What does this mean?)
    None

Time Machine: (What does this mean?)
    Time Machine not configured!

Top Processes by CPU: (What does this mean?)
         4%    WindowServer
         2%    fontd
         2%    com.apple.WebKit.WebContent
         0%    kextd
         0%    SystemUIServer

Top Processes by Memory: (What does this mean?)
    773 MB    kernel_task
    147 MB    Safari
    131 MB    mdworker(
    98 MB    mds_stores
    98 MB    com.apple.WebKit.WebContent

Virtual Memory Information: (What does this mean?)
    12.00 GB    Free RAM 
    4.08 GB    Used RAM (1.23 GB Cached)
    0 B    Swap Used 

Diagnostics Information: (What does this mean?)
    Oct 21, 2015, 12:12:08 PM    Self test - passed