qtcreator crashes with segmentation fault in startup

After I have created a new "Import Project" from existing files and exit and restart qtcreator it crashes with following output:

ele@ele-desktop:~$ qtcreator
QtLockedFile::lock(): file is not opened
QtLockedFile::lock(): file is not opened
QtLockedFile::lock(): file is not opened
QtLockedFile::unlock(): file is not opened
QtLockedFile::lock(): file is not opened
SOFT ASSERT: "m_file.open()" in file /home/qt/work/build/qt-creator/src/plugins/perfprofiler/perfprofilertracemanager.cpp, line 77
Segmentation fault (core dumped)
ele@ele-desktop:~$

What is maybe special about my environment is that my  imported files are behind a symbolic link and my qtcreator project files are in another location than the imported files.

The end result is that I cannot open qtcreator at all, it always crashes.

UPDATE:

Deleted qtcreator 4.11.0 installation and installed 4.11.1. Same segmentation fault but now also leaves behind a background process "clangbackend" that continuously writes to console:

Failed to write data: "QLocalSocket::connectToServer: Invalid name"
QIODevice::write (QLocalSocket): device not open

until I kill it.