I created a second Admin account and logged in as that. Problem doesn't occur.
Booting into Safe Mode in my account: Problem persists.
Here's the Etrecheck report:
EtreCheck version: 4.2.1 (4C020)
Report generated: 2018-04-15 07:18:36
Download EtreCheck from https://etrecheck.com
Runtime: 2:34
Performance: Excellent
Problem: Other problem
Description:
Safari window increases in size
Major Issues: None
Minor Issues:
These issues do not need immediate attention but they may indicate future problems.
Time Machine auto backup disabled - Time Machine auto backups are disabled.
Apps with heavy CPU usage - There have been numerous cases of apps with heavy CPU usage.
Hardware Information:
Mac mini (Late 2014)
Mac mini Model: Macmini7,1
1 2.6 GHz Intel Core i5 (i5-4278U) CPU: 2-core
8 RAM Not upgradeable
BANK 0/DIMM0 - 4 GB DDR3 1600 ok
BANK 1/DIMM0 - 4 GB DDR3 1600 ok
Video Information:
Intel Iris - VRAM: 1536 MB
ASUS VS228 1920 x 1080 @ 60 Hz
HP S2031 1600 x 900 @ 60 Hz
Drives:
disk0 - SanDisk SD7SB7S010T1122 1.02 TB (Solid State - TRIM: Yes)
Internal SATA 6 Gigabit Serial ATA
disk0s1 - EFI (MS-DOS FAT32) [EFI] 210 MB
disk0s2 () 1.02 TB
disk1s1 - Macintosh HD (APFS) 1.02 TB (473.74 GB used)
disk1s2 - Preboot (APFS) [APFS Preboot] 1.02 TB (130 MB used)
disk1s3 - Recovery (APFS) [Recovery] 1.02 TB (3.64 GB used)
disk1s4 - VM (APFS) [APFS VM] 1.02 TB (2.15 GB used)
disk2 - Western Digital My Passport 259F 1.00 TB (Unknown)
External USB 5 Gbit/s
disk2s1 - EFI (MS-DOS FAT32) [EFI] 210 MB
disk2s2 - T*********e (Journaled HFS+) 999.83 GB
disk3 - PNY USB 3.0 FD 31.00 GB (Unknown)
External USB 5 Gbit/s
disk3s1 - B**B (Case-Sensitive Journaled HFS+) 31.00 GB
Mounted Volumes:
disk1s1 - Macintosh HD 1.02 TB (544.13 GB free)
APFS
Mount point: /
disk1s4 - VM [APFS VM] 1.02 TB (544.13 GB free)
APFS
Mount point: /private/var/vm
disk2s2 - T*********e 999.83 GB (43.51 GB free)
Journaled HFS+
Mount point: /Volumes/TimeMachine
disk3s1 - B**B 31.00 GB (30.84 GB free)
Case-Sensitive Journaled HFS+
Mount point: /Volumes/BIAB
Network:
Interface en0: Ethernet
One IPv4 address
2 IPv6 addresses
Interface en8: iPhone
One IPv4 address
Interface en1: Wi-Fi
802.11 a/b/g/n/ac
One IPv4 address
2 IPv6 addresses
iCloud Quota: 3.77 GB available
System Software:
macOS High Sierra 10.13.4 (17E199)
Time since boot: Less than an hour
System Load: 4.92 (1 min ago) 8.98 (5 min ago) 4.98 (15 min ago)
Security:
System Status
Gatekeeper Mac App Store and identified developers
System Integrity Protection Enabled
Kernel Extensions:
/System/Library/Extensions
[Not Loaded] IKStompIO1Driver.kext (1.0.0)
[Not Loaded] daspi.kext (1.5)
System Launch Agents:
[Not Loaded] 7 Apple tasks
[Loaded] 183 Apple tasks
[Running] 102 Apple tasks
[Other] One Apple task
System Launch Daemons:
[Not Loaded] 35 Apple tasks
[Loaded] 186 Apple tasks
[Running] 113 Apple tasks
Launch Daemons:
[Not Loaded] com.rogueamoeba.aceagent.plist (Rogue Amoeba Software, LLC - installed 2018-04-03)
[Not Loaded] com.tclementdev.timemachineeditor.scheduler.plist (Thomas CLEMENT - installed 2017-09-20)
User Launch Agents:
[Not Loaded] com.google.keystone.agent.plist (Google, Inc. - installed 2017-10-06)
User Login Items:
Flux Application (Michael Herf
(/Applications/Flux.app)
Internet Plug-ins:
Flip4Mac WMV Plugin: 3.3.8.1 (installed 2016-10-21)
QuickTime Plugin: 7.7.3 (installed 2018-03-30)
iPhotoPhotocast: 7.0 (installed 2013-04-16)
JavaAppletPlugin: Java 8 Update 144 build 01 (installed 2017-08-16)
Safari Extensions:
BackTrack.safariextz - SideTree.com - Apps for Mac and Web - http://SideTree.com/extensions.html#BackTrack (installed 2018-03-19)
uBlock Origin.safariextz - Raymond Hill/Ellis Tsung - https://www.github.com/el1t/uBlock-Safari (installed 2018-04-03)
Downie Safari Extension - Mac App Store - (installed 2018-04-11)
Translate.safariextz - SideTree.com - Apps for Mac - http://SideTree.com/extensions.html#Translate (installed 2018-03-19)
Tampermonkey.safariextz - Jan Biniok - http://tampermonkey.net (installed 2018-03-19)
3rd Party Preference Panes:
Flip4Mac WMV (installed 2016-10-21)
Java (installed 2017-08-16)
Perian (installed 2013-12-10)
Time Machine:
Skip System Files:
Mobile backups: No
Auto backup: No
Volumes being backed up:
Macintosh HD: Disk size: 1.02 TB - Disk used: 479.87 GB
Destinations:
T*********e [Local] (Last used)
Total size: 999.83 GB
Total number of backups: 68
Oldest backup: 2017-04-29 01:03:12
Last backup: 2018-04-15 01:05:26
Top Processes by CPU:
Process (count) Source % of CPU
WindowServer Apple 3
iconservicesagent (2) Apple 1
coreaudiod Apple 1
kernel_task Apple 1
launchd Apple 1
Top Processes by Memory:
Process (count) Source RAM usage
kernel_task Apple 772 MB
Finder Apple 351 MB
iconservicesagent (2) Apple 136 MB
media-indexer Apple 135 MB
helpd Apple 133 MB
Top Processes by Network Use:
Process Source Input Output
helpd Apple 782 KB 5 KB
mDNSResponder Apple 419 KB 112 KB
apsd Apple 14 KB 21 KB
usbmuxd Apple 6 KB 10 KB
cloudd Apple 7 KB 2 KB
Top Processes by Energy Use:
Process (count) Source Energy usage (0-100)
WindowServer Apple 2
coreaudiod Apple 2
trustd (3) Apple 1
syncdefaultsd 1
iconservicesagent (2) Apple 0
Virtual Memory Information:
Available RAM 4.71 GB
Free RAM 240 MB
Used RAM 3.29 GB
Cached files 4.48 GB
Swap Used 0 B
Diagnostics Information (past 7 days):
2018-04-15 07:06:36 Last Shutdown Cause: 3 - Hard shutdown (once)
2018-04-12 06:34:51 nsurlstoraged Crash (once)
2018-04-11 13:49:10 quicklookd32.app Crash (once)
last threaded generator: com.apple.myriadquicklookgenerator
2018-04-11 07:05:27 QuickLookUIService Crash (once)
2018-04-11 04:42:49 installd CPU (once)
2018-04-09 05:10:56 InfiniteSpaceIII.app CPU (once)
End of report