WordPress “PCLZIP_ERR_BAD_FORMAT (-10) : Invalid archive structure” Solution

When instal­ling plug­ins or the­mes in Word­Press — espe­ci­al­ly when using Ava­da or other pre­mi­um the­mes — users occa­sio­nal­ly encoun­ter the fol­lo­wing error:

PCLZIP_ERR_BAD_FORMAT (-10) : Inva­lid archi­ve struc­tu­re

But what does this error mean and how can it be rec­ti­fied? In this artic­le, we show the most com­mon cau­ses and offer con­cre­te solu­ti­ons.

What does this error mean? #

The mes­sa­ge comes from Word­Press’ own PclZip libra­ry, which unpacks ZIP archi­ves. The “Bad For­mat” error indi­ca­tes that the ZIP file can­not be read or unpa­cked cor­rect­ly.

Common causes #

• Cor­rupt ZIP file
  The uploa­ded file is cor­rupt, incom­ple­te or was down­loa­ded incor­rect­ly.

• Wrong file uploa­ded
  Some­ti­mes the com­ple­te the­me packa­ge (incl. docu­men­ta­ti­on) is uploa­ded by mista­ke ins­tead of just the actu­al the­me or plug­in ZIP.

• Pro­blems with the ser­ver (e.g. memo­ry limit, upload size)
  The ser­ver can­not pro­cess or unpack lar­ge ZIP files.

• Instal­la­ti­on attempt via the the­me its­elf (e.g. Ava­da Plug­in Instal­ler)
  With Ava­da in par­ti­cu­lar, pro­blems often occur when down­loa­ding plug­ins via their UI if the­re is no sta­ble con­nec­tion to the Theme­Fu­si­on ser­vers.

Proposed solutions #

1. Download ZIP file again

Down­load the plug­in or the­me again direct­ly from the ori­gi­nal source. Make sure that the file is com­ple­te.

2. Use the correct ZIP file

If neces­sa­ry, unpack the enti­re packa­ge local­ly and upload only the ZIP file of the plugin/themes, not the enti­re bund­le.

3. Manual installation via FTP

If the instal­la­ti­on via the Word­Press backend fails, the manu­al way helps:

• Unpack the ZIP file local­ly
• Trans­fer the unzip­ped fol­der via FTP to
  /wp-content/plugins/ (for plug­ins) or
  /wp-content/themes/ (for the­mes)
• Then acti­va­te the plugin/theme in the Word­Press dash­board

4. Check PHP and server settings

Increase the fol­lo­wing values in php.ini or via Plesk/cPanel:

upload_max_filesize = 64M
post_max_size = 64M
memory_limit = 256M
max_execution_time = 300

5. Set authorizations correctly (via SSH)

If SSH access exists, incor­rect rights can be cor­rec­ted with the fol­lo­wing com­mand:

cd /var/www/wordpress
chown www-data:www-data . -R
find . -type d -exec chmod 755 {} \;
find . -type f -exec chmod 644 {} \;

Note: If neces­sa­ry, adjust the path to your own Word­Press instal­la­ti­on.

6. Install missing PHP packages

Par­ti­cu­lar­ly when using Ava­da, cer­tain PHP modu­les may be miss­ing. The­se can be che­cked with the fol­lo­wing com­mand and instal­led if neces­sa­ry:

dpkg -l | grep php

If neces­sa­ry, install the fol­lo­wing packa­ges (adapt the ver­si­on depen­ding on the set­up):

apt install php-zip php8.2-zip php8.2-gd php8.2-imagick php8.2-curl

The web ser­ver should then be restar­ted:

systemctl restart apache2
# oder bei NGINX
systemctl restart php8.2-fpm

Conclusion #

In most cases, the “PCLZIP_ERR_BAD_FORMAT” error can be quick­ly rec­ti­fied with clean ZIP files, cor­rect ser­ver con­fi­gu­ra­ti­on and suf­fi­ci­ent sys­tem rights. Espe­ci­al­ly with more com­plex the­mes such as Ava­da, it is also worth taking a look at ser­ver packa­ges and file per­mis­si­ons.

🛠️ Do you need help with error ana­ly­sis or plug-in instal­la­ti­on?
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