I have a desktop computer in my office with Windows 7 Professional (64 bit) SP 1, and my private laptop with Windows Home (64 bit) SP 1. MikTeX 2.9 full 64 bit version is installed on both of them, and both WinEdt 9.1 and WinEdt 10.0 are installed on them. This moment I am not actively using MiKTeX, however, I update it once a week (usually on Wednesday).
The last update went seemingly smoothly on desktop computer but failed on laptop; the update procedure stopped with error message "too meny files". Initially the launch of
MiKTeX Options (Admin)" -> "Refresh FNDB crashed with the same error message. Today I tried to do it once more and seemingly all finished O.K. but now on my laptop in both WinEdt 9.1 and WinEdt 10.0 the menu choice "Options" -> "Execution Modes..." -> "TeX System" leads to nonexistent folder
C:\MiKTeX as TeX Root if Auto-detect is used. I corrected manually TeX Root to the correct folder
C:\Program Files\MiKTeX 2.9, but independently on the value of TeX Root the trial compilation of correct .tex file (one of my published scientific papers) lead to immediate error -
unability to find entry point into MiKTeX209-core.dll.
Warried by all this, I went to my office, in order to test my desktop computer. As usually, I downloaded the newest Norton 360 (antivirus program) updates and then opened both WinEdt 9.1 and WinEdt 10.0. TeX Root was correct in both of them. However, when I tried to compile the same .tex file (my published paper), the translation finished with 0 error messages and 0 output pages. Few seconds later Norton 360 gave the message that its SONAR monitoring function has noticed "suspicious behavior with high risk" of
C:\Program Files\MiKTeX 2.9\miktex\bin\x64\amstex.exe and automatically removed the threat (in fact, quarantined it). My .tex file uses both packages amsmath and amssymb indeed; probably amstex.exe is absolutely necessary. Now if I try to compile .tex file I get the following log file:
===================== Command Line: pdflatex.exe --interaction=errorstopmode --synctex=-1 "Cylindrical_eigenfunctions.tex" Startup Folder: E:\Papers\JQSRT\MiKTeX_parbaude_2016_05_15 Error Launching Console Application PDFLaTeX ... Command Line: pdflatex.exe --interaction=errorstopmode --synctex=-1 "Cylindrical_eigenfunctions.tex" Startup Folder: E:\Papers\JQSRT\MiKTeX_parbaude_2016_05_15 =======================
I seem it is even not worth to try to reinstall MiKTeX because if amstex.exe is evaluated as highly suspicious by Norton 360 SONAR function then it will be quarantined each time when it is launched.