File scan report
Verdict Safe
Is Marlow's Crystal Optimizer-
This widely shared Minecraft optimizer mod JAR has zero detections across 74 antivirus engines and ran cleanly in a sandbox, showing only normal Java activity in the test run.
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Strong evidence · Widely seen for a long time, and nothing harmful found.
This mod can be used normally; obtain it from official mod repositories and keep your antivirus protection enabled.
Good practice2 tips
We found nothing harmful in this file.
Run it only if it came from the project's own website.
Keep your security software and system updates switched on.
No scanner can promise a file is 100% safe.
Antivirus results
0 of 64 flagged
- Flagged 0
- No detection 64
- No result 10
- Code signing Not applicable
- Test run Completed
- First seen 9mo ago
Chapter 02
Why we think so
2 points against it and 4 in its favour, checked against the scan evidence.
The reasoning behind this verdict
None of the 64 antivirus engines that checked it flagged this Java mod, including all major antivirus engines. It has been submitted by 362 different sources over about nine months, and a sandbox run recorded only standard Java launcher and analysis-harness activity with no network connections.
No engine among the 74 flagged the file, and 16 major antivirus engines returned clean results. The file is common and has circulated for 283 days across 362 submitters, which fits a popular Minecraft performance mod. No network contacts were recorded, though no host-reputation cross-check result is available. Six dropped files lack saved verdicts, which is a coverage gap rather than a risk.
What We Detected
None of the 64 antivirus engines that checked it flagged this JAR file, including Kaspersky, ESET-NOD32, BitDefender, Microsoft and Avira. The file has been seen from 362 distinct sources over roughly nine months, consistent with a popular Minecraft client-side optimizer mod.
Threat Behavior
One sandbox run returned a clean result. The recorded activity consists of Java launching the JAR, the sandbox's own tracing agent, Java adjusting permissions on its standard usage-tracking folder, and routine Linux log rotation. Two technique tags related to service creation and defense impairment were mapped, but no process in the recording performs those actions. No domains or IP addresses were contacted, and no complete host-reputation result is available. Six dropped files have no saved verdict.
What To Do Now
The evidence supports using this mod normally. Download mods from official sources such as Modrinth or CurseForge, keep your antivirus enabled, and re-scan if you obtain a different version from an unofficial site.
Where this verdict could be wrong2 caveats
- The sandbox mapped two offensive-looking techniques (service creation and impairing defenses), though the recorded processes do not show the sample doing either; a single run may also miss delayed or conditional behaviour.
- Six dropped files have no saved verdict, and external threat-intel coverage was unavailable for this scan.
These are the assessment's weak points. If you believe one applies to your file, report the verdict and we'll re-review it.
- None of the 64 antivirus engines that checked it flagged the file
- Major antivirus engines including Kaspersky, ESET and Microsoft reported it clean
- Widely shared: 362 different submitters over about nine months
- The sandbox run finished with a clean result and no network contacts were recorded
- The sandbox mapped two offensive-sounding techniques, although the recorded processes do not show the file performing them
- Six files dropped during analysis have no saved verdict yet
6 sources checked · 5 complete · 1 not needed or not applicable. See every source
Chapter 03
What it did in our test
It ran in our isolated test environment; no test environment rated what it did as risky.
Test run summary
Capture complete- 10sandbox rule tags
- 4spawned processes
- 0network contacts
- 13filesystem & mutex artifacts
Includes the sandbox verdicts, 10 mapped techniques, every process, file, registry and network entry and 2 dropped files.
Show the technical evidenceChapter 04
Technical details
None of the 64 antivirus engines that checked it flag it.
Sources checked
Every check behind this verdict
6 sources checked · 5 complete · 1 not needed or not applicable. Complete means the check returned a usable result; it does not mean the file is safe.
File fingerprint
- Last analyzed
- Oct 16, 2026, 4:58 PM UTC
- SHA-256
dc7969358bca82956964a7a96d4aa5911ae267d533ae639aa5ea48c7f50188c5- SHA-1
e8e1866db684c1f6fab8c6b67ebf1f4f57a6de22- MD5
148157d9e6cd822e0c7eb2b1629edf8f
About this file
Marlow's Crystal Optimizer-1.21.11-1.0.5.jar is a JAR file of 108.6 kB.
- Type and size
- JAR · 108.6 kB
- Signer
- Not applicable
- First seen
- Jan 6, 2026On VirusTotal.
- Submitted by
- 362 distinct sources
First scanned
Includes every engine result (74) and how widely the file has been seen.
Show the technical evidenceChapter 05
Questions & answers
Short answers to the 6 questions people ask most about this file.
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Community
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