Nach einem malware check mit avast habe ich was gefunden und gelöscht hört sich jetzt besser an der Mac. 
Anbei Ausgabe von erhrecheck:
EtreCheck version: 4.2.1 (4C020)
Report generated: 2018-05-02 12:29:24
Download EtreCheck from 
https://etrecheck.com
Runtime: 2:26
Performance: Excellent
Problem: Other problem
Major Issues:
  Anything that appears on this list needs immediate attention.
  No Time Machine backup - Time Machine backup not found.
Minor Issues:
  These issues do not need immediate attention but they may indicate future problems.
  Clean up - There are orphan files that could be removed.
Hardware Information:
  MacBook Pro (15-inch, Late 2011)
  MacBook Pro Model: MacBookPro8,2
  1 2,2 GHz Intel Core i7 (i7-2675QM) CPU: 4-core
  8 RAM Upgradeable
    BANK 0/DIMM0 - 4 GB DDR3 1600  ok
    BANK 1/DIMM0 - 4 GB DDR3 1600  ok
  Battery: Health = Normal - Cycle count = 625
Video Information:
  Intel HD Graphics 3000 - VRAM: 512 MB
    Color LCD 1440 x 900
  AMD Radeon HD 6750M - VRAM: 512 MB
Drives:
  disk0 - Samsung SSD 850 EVO 250GB 250.06 GB (Solid State - TRIM: No) 
  Internal SATA 6 Gigabit Serial ATA
    disk0s1 - EFI (MS-DOS FAT32) [EFI] 210 MB
    disk0s2 () [Core Storage Container] 249.72 GB
      disk2 - V*****n (Journaled HFS+) [Fusion Drive] 492.35 GB
    disk0s3 - B*******X () [Recovery] 134 MB
  disk1 - Hitachi HTS542525K9SA00 250.06 GB (Mechanical) 
  Internal SATA 1.5 Gigabit Serial ATA
    disk1s1 - EFI (MS-DOS FAT32) [EFI] 210 MB
    disk1s2 () [Core Storage Container] 249.20 GB
      disk2 - V*****n (Journaled HFS+) [Fusion Drive] 492.35 GB
    disk1s3 - Recovery HD () [Recovery] 650 MB
Mounted Volumes:
  disk2 - V*****n [Fusion Drive]  492.35 GB (367.73 GB free)
  Journaled HFS+
  Mount point: /
 
Network:
  Interface en0: Ethernet
  Interface fw0: FireWire
  Interface en1: Wi-Fi
    802.11 a/b/g/n
    One IPv4 address
    3 IPv6 addresses
  Interface en4: iPhone
  Interface en3: Bluetooth PAN
  Interface bridge0: Thunderbolt Bridge
  iCloud Quota: 4.21 GB available
System Software:
  macOS High Sierra 10.13.4 (17E199) 
  Time since boot: Less than an hour
  System Load: 1.57 (1 min ago) 2.12 (5 min ago) 1.82 (15 min ago)
Security:
  System                      Status
  Gatekeeper                  Mac App Store and identified developers
  System Integrity Protection  Enabled
Kernel Extensions:
  /Library/Application Support/Avast/components/fileshield/signed
    [Loaded]    AvastFileShield.kext (4.0.0 - SDK 10.12)
  /Library/Application Support/Avast/components/proxy/signed
    [Loaded]    AvastPacketForwarder.kext (2.1 - SDK 10.12)
  /Library/Application Support/VirtualBox
    [Loaded]    VBoxDrv.kext (5.2.8)
    [Loaded]    VBoxNetAdp.kext (5.2.8)
    [Loaded]    VBoxNetFlt.kext (5.2.8)
    [Loaded]    VBoxUSB.kext (5.2.8)
System Launch Agents:
  [Not Loaded]  8 Apple tasks
  [Loaded]      175 Apple tasks
  [Running]    109 Apple tasks
  [Other]      One Apple task
System Launch Daemons:
  [Not Loaded]  37 Apple tasks
  [Loaded]      180 Apple tasks
  [Running]    117 Apple tasks
Launch Agents:
  [Not Loaded] com.Priodon_imperence.plist (? 0  - installed 2018-04-15)
  [Other]      com.somerset.sc.plist (? 7cc3d5c9  - installed 2018-04-09)
  [Other]      com.sheristadar.dr.plist (? debd5053  - installed 2018-04-15)
  [Loaded]    6H4HRTU5E3.com.avast.passwords.Agent.plist (AVAST Software a.s. - installed 2018-05-02)
Launch Daemons:
  [Loaded]    6H4HRTU5E3.com.avast.passwords.AgentXPC.plist (AVAST Software a.s. - installed 2018-05-02)
  [Loaded]    com.apple.installer.osmessagetracing.plist (Apple - installed 2018-03-28)
  [Loaded]    com.macpaw.CleanMyMac3.Agent.plist (MacPaw Inc. - installed 2018-05-02)
User Launch Agents:
  [Loaded]    com.macpaw.CleanMyMac3.Scheduler.plist (MacPaw Inc. - installed 2018-05-02)
User Login Items:
  iTunesHelper Programm (Apple - installed 2018-04-02)
    (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
  CleanMyMac 3 Menu Programm (MacPaw Inc. - installed 2018-04-12)
    (/Applications/CleanMyMac 3.app/Contents/MacOS/CleanMyMac 3 Menu.app)
  Kaspersky Virus Scanner Login Item SMLoginItem (Mac App Store - installed 2018-05-02)
    (/Applications/Kaspersky Virus Scanner Free.app/Contents/Library/LoginItems/Kaspersky Virus Scanner Login Item.app)
  Avast Passwords Service SMLoginItem (AVAST Software a.s. - installed 2018-04-05)
    (/Applications/Avast Passwords.app/Contents/Library/LoginItems/Avast Passwords Service.app)
Internet Plug-ins:
  QuickTime Plugin: 7.7.3 (installed 2018-04-09)
3rd Party Preference Panes:
  FUSE (installed 2017-09-21)
Time Machine:
  Time Machine Not Configured!
Top Processes by CPU:
  Process (count)                              Source    % of CPU
  localAuthenticationRemoteService            Apple          11 
  WindowServer                                Apple          8 
  com.apple.preference.security.remoteservice  Apple          6 
  System Preferences                          Apple          3 
  kernel_task                                  Apple          2 
Top Processes by Memory:
  Process (count)                  Source                RAM usage
  kernel_task                      Apple                    767 MB
  com.apple.WebKit.WebContent (9)   Apple                    372 MB
  com.apple.WebKit.Networking (10)  Apple                    210 MB
  kvs                              Mac App Store            132 MB
  com.avast.daemon                  AVAST Software a.s.      121 MB
Top Processes by Network Use:
  Process          Source                Input  Output
  com.avast.daemon  AVAST Software a.s.   152 KB    2 KB
  mDNSResponder    Apple                  25 KB   23 KB
  apsd              Apple                  12 KB    9 KB
  cloudd            Apple                  9 KB    2 KB
  netbiosd          Apple                  4 KB  1002 B
Top Processes by Energy Use:
  Process (count)  Source      Energy usage (0-100)
  WindowServer    Apple        5
  coreduetd        Apple        0
  launchd          Apple        0
  CleanMyMac 3    MacPaw Inc.  0
  loginwindow      Apple        0
Virtual Memory Information:
  Available RAM    3.95 GB
  Free RAM          397 MB
  Used RAM        4.05 GB
  Cached files    3.56 GB
  Swap Used            0 B
Clean up:
  /Library/LaunchAgents/com.somerset.sc.plist
    /Library/somerset.sc/somerset.sc.app/Contents/MacOS/somerset.sc
    Executable not found
  /Library/LaunchAgents/com.sheristadar.dr.plist
    /Library/sheristadar.dr/sheristadar.dr.app/Contents/MacOS/sheristadar.dr
    Executable not found
Diagnostics Information (past 7 days):
  2018-05-02 01:04:33 com.avast.daemon CPU (once)
End of report