I wonder what should I do as UXUI designer when I have a project where unfortunately I do not have access to possibles final users but I really need to do a user research in order to start building my personas etc etc.
At the moment I using my experience in similar projects, some user reviews from other similar products I found on the Internet or competitors products and finally my intuition but I feel I am taking shots in the dark.
What should I do? What is the process in this case?
I answer another version of this question (though yours is far more succinct) over there.
Drink a cup of coffee with support. They usually hear enough frustrations directly from clients, sometimes on a daily basis. Do watch out you don't get wrapped in their personal bias (believes, wishes etc). Or do you have to design for a new product?
Very common problem
*I would do a bunch of competitor research for this. You'll pick up common practices and maybe get a feel for what might work.
*Access to any analytics? This can tell you loads and is another great place to start.
*As someone said, speaking to support staff is another great place to pick up on possible pain points "the common problems are..."
Then have a go at proto-personas and user journeys and see if they make sense with colleagues.
Your goal, I assume, is to discover how people do the things your system supports.
Do you have access to people who do those things, even if they're not doing them on your system? In fact, it's sometimes better to discover what people's tasks are and how they accomplish them outside of your current application. You'll get more generalized results that way.
Instead of "Users do this by accessing our 'Tools' tab" you'll discover "People do this by collecting the following information beforehand in preparation... and breaking the task into the following sub-tasks... "
(And I agree, make friends with the Analytics and Customer Service departments.)
Depending on your product, I have found social media to be really helpful for this.
I was working with a startup that didn't actually have many users yet, so I went out and found people with job titles on LinkedIn and asking them for their expert opinions. I also asked Facebook friends to introduce me to anyone who was a potential user. I arranged to take them out to lunch of hopped on a call. From here I was able to build persona's, customer journeys (from users using competitors), and job tasks, and user stories.
Sending them a small suprise as a thank you, is also really good practice. Then was able to return to them to test paper proto-types, ect.