Apt-get update encountered unlink delete file error?

delete a file in sources.list.d/,
and then perform the update operation, and the following error occurs
restoring the file is also useless
did not search for what the damn file is.
searched the Internet for a long time, but couldn"t find any useful information.
Urumqi 18.04

:/etc/apt$ sudo apt-get update
:1 http://dl.google.com/linux/chrome/deb stable InRelease
:2 http://dl.google.com/linux/chrome/deb stable Release
:4 http://ppa.launchpad.net/hzwhuang/ss-qt5/ubuntu xenial InRelease      
:5 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial InRelease
:6 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-updates InRelease
:7 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-backports InRelease
:8 https://mirrors.tuna.tsinghua.edu.cn/ubuntu xenial-security InRelease
...                        
W:  unlink  partialapt-get  - pkgAcquire::Clean (21: )

have you ever experienced this? Or is there any solution "?

Mar.07,2021

sources.list.d is the source address of the third-party package

you can just delete it and add it:
these files are the default ones:

cassou-ubuntu-emacs-xenial.list  
google-chrome.list               
mongodb-org-3.6.list

`
locate partialapt-get
rm-rf partialapt-get
`
is fine. I didn't look for this file carefully at that time.

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b38555-2c133.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b38555-2c133.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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