Suggestion:
Download EtreCheck (it's free), run it, post the results here.
Thanks for this - here are the results:
Hardware Information:
MacBook Air
MacBook Air - model: MacBookAir6,2
1 1,3 GHz Intel Core i5 CPU: 2 cores
8 GB RAM
Video Information:
Intel HD Graphics 5000 - VRAM: (null)
Audio Plug-ins:
BluetoothAudioPlugIn: Version: 5.0.5
iSightAudio: Version: 7.7.3
AirPlay: Version: 2.0
AppleAVBAudio: Version: 503.2
AppleTimeSyncAudioClock: Version: 1.0
System Software:
macOS 10.12.6 (16G29) - Uptime: 12 days 9:36:24
Disk Information:
APPLE SSD SD0256F disk0 : (251 GB)
EFI (disk0s1) <not mounted>: 209,7 MB
disk0s2 (disk0s2) <not mounted>: 250,14 GB
Recovery HD (disk0s3) <not mounted>: 650 MB
USB Information:
TOSHIBA External USB 3.0
Apple Inc. BRCM20702 Hub
Apple Inc. Bluetooth USB Host Controller
FireWire Information:
Thunderbolt Information:
Apple Inc. thunderbolt_bus
Kernel Extensions:
Problem System Launch Daemons:
[failed] com.apple.captiveagent.plist
[failed] com.apple.DataDetectorsSourceAccess.plist
[failed] com.apple.InstallerDiagnostics.installerdiagd.plist
[failed] com.apple.mobile.keybagd.plist
[failed] com.apple.periodic-monthly.plist
[failed] com.apple.periodic-weekly.plist
[failed] com.apple.systemstats.analysis.plist
[failed] com.apple.wdhelper.plist
[failed] com.apple.xpc.smd.plist
Problem System Launch Agents:
[failed] com.apple.CallHistoryPluginHelper.plist
[failed] com.apple.CallHistorySyncHelper.plist
[failed] com.apple.cmfsyncagent.plist
[failed] com.apple.DiskArbitrationAgent.plist
[failed] com.apple.icloud.fmfd.plist
[failed] com.apple.rcd.plist
[failed] com.apple.xpc.loginitemregisterd.plist
[loaded] com.openssh.ssh-agent.plist
Launch Daemons:
[loaded] com.bombich.ccchelper.plist
[loaded] de.verbi.SMJobBlessHelper12.plist
Launch Agents:
User Launch Agents:
[loaded] com.adobe.ARM.[...].plist
[loaded] com.akamai.single-user-client.plist
[loaded] com.avast.home.userinit.plist
[loaded] com.avast.secureline.home.userinit.plist
[loaded] com.dropbox.DropboxMacUpdate.agent.plist
[loaded] com.setapp.DesktopClient.SetappAgent.plist
[failed] com.setapp.DesktopClient.SetappUpdater.plist
[loaded] com.skype.skype.shareagent.plist
User Login Items:
Box Sync
Alfred
BetterTouchTool
Dropbox
Google Drive
TotalFinder
Default Folder X
SpiderOakONE
NoteBookHelper.service
CrossOver CD Helper
HazelHelper
Box Local Com Server
DEVONthink Sorter
3rd Party Preference Panes:
Air Display Preferences
Akamai NetSession Preferences
Citrix ShareFile Sync
Flash Player
GPGPreferences
Hazel
Logitech Preference Manager
MacFUSE (Tuxera)
TeXDistPrefPane
Tuxera NTFS
Internet Plug-ins:
QuickTime Plugin.plugin
Flash Player.plugin
FlashPlayer-10.6.plugin
User Internet Plug-ins:
Bad Fonts:
None
Time Machine:
Skip System Files: NO
Mobile backups: OFF
Auto backup: YES
Volumes being backed up:
Destinations:
Time machine [Local]
Total size: 750 GB
Total number of backups: 22
Oldest backup: 2017-07-18 21:00:20 +0000
Last backup: 2017-08-30 06:13:20 +0000
Size of backup disk: Excellent
Backup size 750 GB > (Disk size Zero KB X 3)
Other storage [Local] (Last used)
Total size: 249,73 GB
Total number of backups: 5
Oldest backup: 2017-09-01 22:22:50 +0000
Last backup: 2017-09-02 03:54:21 +0000
Size of backup disk: Excellent
Backup size 249,73 GB > (Disk size Zero KB X 3)
Top Processes by CPU:
12% WindowServer
4% EtreCheck
3% Box Sync Monitor
2% coreaudiod
1% Box Sync
1% hidd
0% Safari
0% Google Drive
0% apsd
0% Amphetamine
Top Processes by Memory:
778 MB fsck_hfs
336 MB PDF Expert
205 MB Safari
172 MB Google Drive
172 MB Mail
123 MB Skype
98 MB Microsoft PowerPoint
90 MB Finder
90 MB MailMate
90 MB mds_stores
Virtual Memory Statistics:
73 MB Free RAM
2.39 GB Active RAM
2.33 GB Inactive RAM
1.92 GB Wired RAM
205.30 GB Page-ins
1.00 GB Page-outs