Pro-Mini commo fail

I keep getting fail messages when I try to upload a sketch to my 5v, ATmega 328, 16MHz Pro Mini. This is the fail message:

avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0xfb

Last night I was able to modify and upload sketches. I was also able to view the serial monitor to watch the distances scroll by. Now I can't upload sketches, and the serial monitor is blank.

I am able to upload code to an arduino PRO using the FTDI cable and the same settings, etc.

It leads me to believe the problem lies with the pro mini. In a nutshell, I was able to upload code and now I'm not. Is it possible that the Pro Mini failed?

It is common for people to accidentally connect the FTDI connector upside down on Pro Minis. Perhaps you are doing that?

If you continue to have problems, go into the IDE preferences and check show verbose output during upload. Connect the FTDI, take a picture for us to show how you have it connected, attempt upload and post the output of the verbose messages. Describe what the LEDs on the Pro Mini show when you attempt upload.

As I said, I am able to connect and upload to other boards with the FTDI, same settings, etc.

This is the verbose message. I only saw the green LED on the Pro Mini flash once for about a half second. The red power LED is on.

Sketch uses 1,066 bytes (3%) of program storage space. Maximum is 30,720 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2,039 bytes for local variables. Maximum is 2,048 bytes.
C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avrdude -CC:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf -v -patmega328p -carduino -PCOM3 -b57600 -D -Uflash:w:C:\Users\Owner2\AppData\Local\Temp\build9c9ef3bdfe2fccb480bc6e4bac749e41.tmp/Blink.ino.hex:i

avrdude: Version 6.0.1, compiled on Apr 15 2015 at 19:59:58
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2009 Joerg Wunsch

System wide configuration file is “C:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf”

Using Port : COM3
Using Programmer : arduino
Overriding Baud Rate : 57600
avrdude: ser_open(): can’t open device “\.\COM3”: Access is denied.

avrdude done. Thank you.

Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.
Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.
Exception in thread “Thread-138” java.util.ConcurrentModificationException
at java.util.LinkedList$LLSpliterator.forEachRemaining(LinkedList.java:1239)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
at cc.arduino.contributions.libraries.LibrariesIndexer.rescanLibraries(LibrariesIndexer.java:123)
at cc.arduino.contributions.libraries.LibrariesIndexer.setLibrariesFolders(LibrariesIndexer.java:102)
at processing.app.BaseNoGui.onBoardOrPortChange(BaseNoGui.java:834)
at processing.app.Base.onBoardOrPortChange(Base.java:1245)
at processing.app.Editor$DefaultExportHandler.run(Editor.java:2439)
at java.lang.Thread.run(Thread.java:745)

Also there are two Tx pins and two Rx pins on the Pro Mini. There is continuity between the two Rx pins on this Pro Mini but no continuity between the two Tx pins on this Pro Mini. On my other never used Pro Mini, there is continuity. I would say somehow there is some fail, but how and why? As I said, it was working as expected earlier. Of course I would swap out the never used Pro Mini for the bad one, but the bad one is soldered into the breadboard. I doubt I could de-solder all those pins.

I think with "can't open device "\.\COM3": Access is denied" you are not even getting to the point of trying to program the Pro Mini. You are not opening the FTDI at all. That is bad.

That is really unfortunate news about the continuity between the two TX pins, it sounds like you may have multiple problems, and problem with the traces or soldering on the Pro Mini may be one of them. Looking at the Pro Mini schematic they are definitely connected on the Pro Mini board.

De-soldering is indeed difficult. If you have soldered with header pins and can clip all the pins into 2 pieces to get the bad board out of the way, that is usually the easiest way. That way you can desolder one pin at a time from your main board by just heating the joint and pulling the cut pin with tweezers.