spyder: Spyder unable to load Spyder 3 icon theme, same issue as #18642

Issue Report Checklist

• Searched the issues page for similar reports
• Read the relevant sections of the Spyder Troubleshooting Guide and followed its advice
• Reproduced the issue after updating with conda update spyder (or pip, if not using Anaconda)
• Could not reproduce inside jupyter qtconsole (if console-related)
• Tried basic troubleshooting (if a bug/error)
  • Restarted Spyder
  • Reset preferences with spyder --reset
  • Reinstalled the latest version of Anaconda
  • Tried the other applicable steps from the Troubleshooting Guide
• Completed the Problem Description, Steps to Reproduce and Version sections below

Problem Description

I just installed spyder through anaconda, it was working fine for a few minutes, until I updated MiKTeX (TeX distribution to write LaTeX documents). After that, I got the exact same issue as the one described in #18642, which I recall below:

Spyder refuses to load the icon theme of Spyder 3 and falls back to the icon theme of Spyder 2, which is no longer adapted (many spyder icons are replaced by red crosses). Selecting theme 3 can be done in tools -> preferences -> appearance -> main interface, but it then asks to restart spyder to apply the changes, and when restarting Spyder keeps refusing to load them 3.

What steps reproduce the problem?

1. Open spyder
2. Go to tools -> preferences -> appearance -> main interface and select Spyder 3 in “icon theme”
3. Restart spyder and see the error message “Spyder was unable to load the Spyder 3 icon theme. That’s why it’s going to fallback to the theme used in Spyder 2. For that, please close this window and start Spyder again”

What is the expected output? What do you see instead?

The expected behaviour is Spyder 3 to work properly as this issue is indicated as “closed” in #18642

Versions

• Spyder version: 5.4.3
• Python version: 3.11.5
• Qt version: 5.15.2
• PyQt version: 5.15.7
• qtawesome version: 1.2.3
• Operating System name/version: Windows 10 Entreprise, version 21H2

Dependencies

# Mandatory:
atomicwrites >=1.2.0                             :  1.4.0 (OK)
chardet >=2.0.0                                  :  4.0.0 (OK)
cloudpickle >=0.5.0                              :  2.2.1 (OK)
cookiecutter >=1.6.0                             :  1.7.3 (OK)
diff_match_patch >=20181111                      :  20200713 (OK)
intervaltree >=3.0.2                             :  3.1.0 (OK)
IPython >=7.31.1,<9.0.0,!=8.8.0,!=8.9.0,!=8.10.0 :  8.15.0 (OK)
jedi >=0.17.2,<0.19.0                            :  0.18.1 (OK)
jellyfish >=0.7                                  :  1.0.1 (OK)
jsonschema >=3.2.0                               :  4.17.3 (OK)
keyring >=17.0.0                                 :  23.13.1 (OK)
nbconvert >=4.0                                  :  6.5.4 (OK)
numpydoc >=0.6.0                                 :  1.5.0 (OK)
paramiko >=2.4.0                                 :  2.8.1 (OK)
parso >=0.7.0,<0.9.0                             :  0.8.3 (OK)
pexpect >=4.4.0                                  :  4.8.0 (OK)
pickleshare >=0.4                                :  0.7.5 (OK)
psutil >=5.3                                     :  5.9.0 (OK)
pygments >=2.0                                   :  2.15.1 (OK)
pylint >=2.5.0,<3.0                              :  2.16.2 (OK)
pylint_venv >=2.1.1                              :  2.3.0 (OK)
pyls_spyder >=0.4.0                              :  0.4.0 (OK)
pylsp >=1.7.2,<1.8.0                             :  1.7.2 (OK)
pylsp_black >=1.2.0                              :  1.2.1 (OK)
qdarkstyle >=3.0.2,<3.2.0                        :  3.0.2 (OK)
qstylizer >=0.2.2                                :  0.2.2 (OK)
qtawesome >=1.2.1                                :  1.2.3 (OK)
qtconsole >=5.4.2,<5.5.0                         :  5.4.2 (OK)
qtpy >=2.1.0                                     :  2.2.0 (OK)
rtree >=0.9.7                                    :  1.0.1 (OK)
setuptools >=49.6.0                              :  68.0.0 (OK)
sphinx >=0.6.6                                   :  5.0.2 (OK)
spyder_kernels >=2.4.3,<2.5.0                    :  2.4.4 (OK)
textdistance >=4.2.0                             :  4.2.1 (OK)
three_merge >=0.1.1                              :  0.1.1 (OK)
watchdog >=0.10.3                                :  2.1.6 (OK)
zmq >=22.1.0                                     :  23.2.0 (OK)

# Optional:
cython >=0.21                                    :  None (NOK)
matplotlib >=3.0.0                               :  3.7.2 (OK)
numpy >=1.7                                      :  1.24.3 (OK)
pandas >=1.1.1                                   :  2.1.1 (OK)
scipy >=0.17.0                                   :  1.11.3 (OK)
sympy >=0.7.3                                    :  1.11.1 (OK)