After I upgrade to Mojave I have a major error
Hei I got this error yesterday and this is what I do.

For my case, I got Sandbox: LKplUJjx(76) error, so check detail log with console.
After found the path file, I delete that directory then restart. Now my Mojave can run normally even thought I don't know whether this file is important or no.

error   13:13:02.393416 +0700   kernel  Sandbox: LKplUJjx(76) System Policy: deny(1) file-write-create /Library/Updates/.dat.nosync004c.RCzwHW
error   13:13:02.393448 +0700   sandboxd    Sandbox: LKplUJjx(76) System Policy: deny(1) file-write-create /Library/Updates/.dat.nosync004c.q7zMU7
Violation:       System Policy: deny(1) file-write-create /Library/Updates/.dat.nosync004c.q7zMU7 
Process:         LKplUJjx [76]
Path:            /Library/LKplUJjx/LKplUJjx.app/Contents/MacOS/LKplUJjx
Load Address:    0x1038bc000
Identifier:      org.nn.updater
Version:         1.0 (1.0)
Code Type:       x86_64 (Native)
Parent Process:  launchd [1]
Responsible:     /Library/LKplUJjx/LKplUJjx.app/Contents/MacOS/LKplUJjx [76]
User ID:         0

Date/Time:       2018-11-25 13:13:02.234 GMT+7
OS Version:      Mac OS X 10.14.1 (18B75)
Report Version:  8


MetaData: {"path":"\/Library\/Updates\/.dat.nosync004c.q7zMU7","profile":"platform","storage-class":"SoftwareUpdate","normalized_target":["Library","Updates",".dat.nosync004c.q7zMU7"],"vnode-type":"REGULAR-FILE","errno":1,"action":"deny","pid":76,"rdev":0,"responsible-process-pid":76,"primary-filter":"path","profile-flags":0,"process":"LKplUJjx","flags":21,"uid":0,"platform_binary":"no","operation":"file-write-create","build":"Mac OS X 10.14.1 (18B75)","primary-filter-value":"\/Library\/Updates\/.dat.nosync004c.q7zMU7","platform-binary":false,"suffix":".dat.nosync004c.q7zMU7","responsible-process-path":"\/Library\/LKplUJjx\/LKplUJjx.app\/Contents\/MacOS\/LKplUJjx","summary":"deny(1) file-write-create \/Library\/Updates\/.dat.nosync004c.q7zMU7","platform-policy":true,"hardware":"Mac","process-path":"\/Library\/LKplUJjx\/LKplUJjx.app\/Contents\/MacOS\/LKplUJjx","target":"\/Library\/Updates\/.dat.nosync004c.q7zMU7","file-flags":524288}

Thread 0 (id: 580):
0   libsystem_kernel.dylib          0x00007fff5ceafbce __open + 10
1   Foundation                      0x00007fff31f2534f _NSWriteDataToFileWithExtendedAttributes + 224
2   Foundation                      0x00007fff31f24e5b writeStringToURLOrPath + 216
3   LKplUJjx                        0x00000001038bd8d6
4   libdyld.dylib                   0x00007fff5cd7608d start + 1
5   LKplUJjx                        0x0000000000000001

Binary Images:
       0x1038bc000 -        0x1038bffff  org.nn.updater (1.0 - 1.0) &lt;170a4f2b-d3c0-3f9d-9729-3b9cd77f5484&gt; /Library/LKplUJjx/LKplUJjx.app/Contents/MacOS/LKplUJjx
    0x7fff31ee3000 -     0x7fff322b1fff  com.apple.Foundation (6.9 - 1560.12) &lt;b5dc275c-12c9-320a-a117-c8fe9034931a&gt; /System/Library/Frameworks/Foundation.framework/Versions/C/Foundation