Today I learned the very hard way that Clarion Trace can cause some major havoc, at least in Clarion 6. Late yesterday I was working on applications that connect to a MS-SQL database. Everything was good and running smoothly, but I was trying to optimize several linked browses so I turned Tracing on to see what the driver was sending to the back end. Once I was done, I turned Tracing off, or so I thought. I had accidentally left the "Flush contents" checkbox checked when I closed the program. I took a break and got myself some coffee.
When I got back all hell broke lose. All the programs that connect to the MS-SQL database were crashing when they started and tried to connect to the database. So was Clarion's dictionary editor when I tried to connect to it and import a table, just to see if Clarion could connect. This morning I set out to find what was going on. I restored the Clarion 6 BIN folder from a backup as well as the 3rdParty\Bin folder. No change.
As the client I'm working with was zipping up his Clarion 6 environment to FTP to me, I created a small application in Clarion 8 to see if it would have the same problem. No problems, so that definitely indicated that the problem was a Clarion 6 problem only. As I was going through the BIN folder to look for anything suspicious, I saw trace.exe and ran it and jumped to the MS-SQL driver. "Flush content" was checked. I've left it checked before as I recall with the SQL Anywhere driver without any issues. So I unchecked it and tried one of the programs. Lo and behold it ran fine! So I turned "Flush content" back on and again the program crashed.
So if your program all of a sudden starts crashing when accessing a database, check the Trace settings for that database driver. Hope this helps someone to debug a rather obscure problem:)