After installation of 3.4.0 version, when trying adding any record (Contact, Lead, Competition ...) foloowing message appears: There is no active transaction
Below following stack is reported:
Guide me please in order to find a root cause.
@ninijka check your cron and webserver requirements.
Thank you for your quick feedback.
I installed it on Windows 10 (no cron) with Wamp web server: PHP 5.6.25 and MySQL 5.7.14
All setting in php.ini I set up according to installer requirements.
For me it looks like database permission problem.
But I'm connected with user root to MySQL database and I've got all priviledges:
What exactly do you advice to check?
look at my comment
On Windows you need an entry in the task scheduler (example from my win10 dev installation):

Yhank you for your support.
I've checked and I don't have any task in task scheduler.
I've started vtigercron.bat manually and no effect.
Still have problems with creation of data.
I don't think that this cron job is related to my problem.
@ninijka check your WAMP setting for MySQL. Let's repeat settings like on screenshot below. Check sql-mode -> user mode.

For correct cron workability you need to configure rigth paths for next lines at vtigercron.bat
set VTIGERCRM_ROOTDIR="C:\wamp\www\ys"
set PHP_EXE="C:\wamp\bin\php\php5.6.25\php.exe"
Exactly STRICT_TRANS_TABLES was a root cause.
I found it earlier in following issue: https://github.com/YetiForceCompany/YetiForceCRM/issues/1573
and fixed.
But thank you very much for great help.
Stay cool.