I've been getting the same since upgrading to V15.56. That was actually a fix to a serious bug we were having and now have hundreds of string variables now stored and overwritten by corrupted garbage with breaks hundreds of tests stopping us testing.
https://community.smartbear.com/t5/TestComplete-Questions/Corrupted-Project-and-Keyword-Test-variables/m-p/259412#M112759
We are going to use a Notepad++ macro to find all the variables in the various files and use a conversion utitlity to try and set them back to their correct values.
We have opened ticket 00574549 for this. We're worried other projects will be impacted.
The quality of TC releases has become poorer over the last 2-3 years and we want to have a conversation with our account manager to get some feedback from the Product Manager. We dont want to make further investments if this is now the norm. Its dissapointing to see, as I've used it for 12 years and its never been like this.
