Libreoffice very slow to open (Linux, Kubuntu)

Recently Libreoffice has become very slow to open on my computer. It takes several minutes just to open. My cOS is Kubuntu20.04.

I have tried to:

• purge it and reinstall it
• install the latest version from a deb package

I have also tried to follow the tips on this page though my OS is Linux:

• run LibreOffice in safe mode
• toggle openCL
• remove anti-aliasing

It changed nothing.

I have run a strace libreoffice but I can not interprete the results. Here are the last few lines that I get before libreoffice gets struck. I can add the whole report if needed.

connect(3, {sa_family=AF_UNIX, sun_path="/tmp/OSL_PIPE_1000_SingleOfficeIPC_b910dfc6e06b87d13cbea62e8047c298"}, 110) = -1 ENOENT (No such file or directory)
close(3)                                = 0
stat("/proc/version", {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
stat("/usr/lib/libreoffice/program/", {st_mode=S_IFDIR|0755, st_size=20480, ...}) = 0
openat(AT_FDCWD, "/sys/dev/block/8:0/queue/rotational", O_RDONLY) = 3
close(3)                                = 0
mmap(NULL, 8392704, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_STACK, -1, 0) = 0x7f7d73a20000
mprotect(0x7f7d73a21000, 8388608, PROT_READ|PROT_WRITE) = 0
clone(child_stack=0x7f7d7421f630, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, parent_tid=[25343], tls=0x7f7d74220700, child_tidptr=0x7f7d742209d0) = 25343
futex(0x55daba28d610, FUTEX_WAKE_PRIVATE, 1) = 1
futex(0x55daba28d610, FUTEX_WAKE_PRIVATE, 1) = 0
futex(0x55daba28d838, FUTEX_WAIT_PRIVATE, 0, NULL) = 0
futex(0x55daba28d840, FUTEX_WAKE_PRIVATE, 1) = 0
read(5, "/usr/lib/jvm/java-11-openjdk-amd"..., 4096) = 209
close(5)                                = 0
pipe([3, 4])                            = 0
clone(child_stack=0x7f7d7421f630, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, parent_tid=[25364], tls=0x7f7d74220700, child_tidptr=0x7f7d742209d0) = 25364
futex(0x55daba28e890, FUTEX_WAKE_PRIVATE, 1) = 1
futex(0x55daba28e890, FUTEX_WAKE_PRIVATE, 1) = 0
futex(0x55daba28d838, FUTEX_WAIT_PRIVATE, 0, NULL) = 0
futex(0x55daba28d840, FUTEX_WAKE_PRIVATE, 1) = 0
close(4)                                = 0
futex(0x55daba28ece8, FUTEX_WAIT_BITSET_PRIVATE|FUTEX_CLOCK_REALTIME, 0, {tv_sec=1639832977, tv_nsec=373455000}, FUTEX_BITSET_MATCH_ANY

The command apt-cache policy libreoffice gives

libreoffice:
  Installed: (none)
  Candidate: 1:7.2.3~rc2-0ubuntu0.20.04.1~lo1
  Version table:
     1:7.2.3~rc2-0ubuntu0.20.04.1~lo1 500
        500 http://ppa.launchpad.net/libreoffice/ppa/ubuntu focal/main amd64 Packages
     1:7.1.7-0ubuntu0.21.04.1~bpo20.04.1 100
        100 http://fr.archive.ubuntu.com/ubuntu focal-backports/universe amd64 Packages
     1:6.4.7-0ubuntu0.20.04.2 500
        500 http://fr.archive.ubuntu.com/ubuntu focal-updates/universe amd64 Packages
        500 http://security.ubuntu.com/ubuntu focal-security/universe amd64 Packages
     1:6.4.2-0ubuntu3 500
        500 http://fr.archive.ubuntu.com/ubuntu focal/universe amd64 Packages

The command lowriter --version gives:

LibreOffice 7.2.3.2 20(Build:2)

Do you know what the problem is and what I could do ?

Thank you

You have to try resetting its per-user configuration by

mv ~/.config/libreoffice ~/.config/libreoffice_old

and then start LibreOffice again.

One thing that could cause it is an abnormally large number of installed fonts (could something have done that recently?) or a corrupted font cache

Try running sudo fc-cache -f -v to reset your font cache.

If that doesn't work compare your ~/.local/share/fonts, /usr/share/fonts/ and /usr/local/share/fonts contents with that of a fresh installation (e.g. install Ubuntu on a VM) i.e.

cd /usr/share/fonts
find . >> ~/fontlist.txt
cd /usr/local/share/fonts
find . >> ~/fontlist.txt
cd ~/.local/share/fonts
find . >> ~/fontlist.txt

diff ~/fontlist.txt ~/vmlist.txt

to see if it's abnormally larger (or maybe there's a rogue font, try backing up your fonts and replace them with the contents of a stock installation, reset the cache, and try again)

Edit: Just to try things out, try refreshing your icon cache as well.